The pro se employee appeals from the findings of fact of Compensation Judge John E. Jansen, served and filed on November 15, 1994, in which the compensation judge found on referral of a question of fact by this court on August 31, 1994, that the employee did not file his appeal from the Findings and Order of Compensation Judge Nancy Olson until April 28, 1994. We affirm, and accordingly grant the motion of the employer and insurer to dismiss the employee’s appeal from the Findings and Order of Compensation Judge Nancy Olson, served and filed March 28, 1994.

The sole issue on referral was the date on which the employee filed his appeal. The 30th day after service and filing of Compensation Judge Nancy Olson’s Findings and Order in this matter was April 27, 1994. Thus, if the employee’s initial appeal was not filed until April 28, 1994, the 31st day, the appeal would not be timely, and this court would lack jurisdiction to hear the appeal.

The employee’s typed notice of appeal and proof of service are dated April 28, 1994, and were date stamped as received by the Office of Administrative Hearings (OAH) on April 28, 1994. However, the court administrator at OAH crossed off the date stamp on the documents, and wrote in the date of April 27, 1994, above her signature. The employee asserted at oral argument before this court on August 29, 1994, that he attempted to file a notice of appeal and proof of service, and to pay the $25.00 filing fee, on April 27, 1994, but was prevented from doing so by the actions of OAH employees.

This court was unable to determine from the facts and documents available to us the exact circumstances surrounding the filing of the employee’s appeal. We accordingly referred this matter on August 31, 1994, pursuant to Minn. Stat. § 176.381, to the Chief Administrative Law Judge for assignment to a compensation judge for a hearing and findings regarding the specific facts surrounding the filing or attempted filing of the employee’s appeal on April 27 and April 28, 1994, including:

On October 11, 1994, a hearing was held before Compensation Judge John E. Jansen. At the hearing, the judge heard testimony from the employee, Ben K. Abanukam; Leslie Doolittle, court administrator at OAH; Kathleen Klinkenberg, a secretary at OAH; LaVell Geer, a clerk-typist/receptionist at OAH; and Judy West, a clerk-typist II at OAH. On November 15, 1994, Judge Jansen issued his findings of fact, finding, among other things, that the employee did not effectively file or attempt to file his appeal within 30 days of March 28, 1994, but rather attempted to file such appeal on the 31st day thereafter, on April 28, 1994. (Finding 7.) The employee appeals from all of the findings of the compensation judge.

In reviewing cases on appeal, the Workers’ Compensation Court of Appeals must determine whether “the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted.” Minn. Stat. § 176.421, subd. 1 (1992). Substantial evidence supports the findings if, in the context of the entire record, “they are supported by evidence that a reasonable mind might accept as adequate.” Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984). Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed. Id. at 60, 37 W.C.D. at 240. Similarly, “[f]actfindings are clearly erroneous only if the reviewing court on the entire evidence is left with a definite and firm conviction that a mistake has been committed.” Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975). Findings of fact should not be disturbed, even though the reviewing court might disagree with them, “unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of the evidence or not reasonably supported by the evidence as a whole.” Id.

The compensation judge determined, based on the testimony given under oath by OAH employees, that on April 27, 1994, the employee, Mr. Abanukam, who was proceeding pro se, made one telephone call and two personal visits to OAH. During his first visit, in the morning on that date, the employee mentioned to Ms. Geer that the last day for filing an appeal from Judge Nancy Olson’s decision, filed March 28, 1994, was April 27, 1994. Ms. Geer advised him that if it was the last day to file his appeal, OAH would need to “have the appeal by 4:30 [p.m.].” She further testified that, although she told him that Ms. Doolittle would have to explain the indigent transcript affidavit and fee to him, she [Ms. Geer] also repeatedly told Mr. Abanukam that she would accept his appeal and the $25.00 appellate fee without the indigent transcript affidavit and fee. Mr. Abanukam left OAH that morning without filing his appeal. (Finding 1a; T. 116, 121-22.)

On April 27, 1994, the employee talked by telephone with Ms. Doolittle, discussed procedural questions about appeal requirements, and was advised that a packet of appeal information and materials would be available for him to pick up at the receptionist window at OAH later that day. (Finding 1b; T. 66.) During the afternoon of April 27, 1994, between approximately 3:15 p.m. and 3:45 p.m., Mr. Abanukam returned to OAH. Ms. Klinkenberg handed him the packet of materials prepared by Ms. Doolittle. The packet contained a copy of the applicable portion of Minn. Stat. § 176.421, a copy of Minn. R. 1415.2900, subp. 7E, and a blank form entitled “Notice of Appeal to Workers’ Compensation Court of Appeals.” The following language appears at the bottom of the notice of appeal form:

Mr. Abanukam testified that it was his understanding from the information provided to him by the clerical staff at OAH on April 27, 1994, that he needed to either make arrangements for payment for a transcript of the hearing, or file an indigency affidavit and request that OAH pay for the transcript. (Mem. at 4; Resp. Exh. 1.) He claimed that on April 27, 1994, he attempted to file, at OAH, a separate Notice of Appeal document which he had prepared, allegedly with the assistance of Department of Labor and Industry personnel, but that this document was refused by the receptionist at OAH. (T. 142-43, 186.) Mr. Abanukam further testified that this document was included with the documents that he presented and filed on April 28, 1994. The compensation judge concluded that Mr. Abanukam was apparently claiming that the purported April 27 Notice of Appeal had somehow disappeared after it was presented to the OAH along with the April 28 documents described in Finding 4. (T. 146-157.) The compensation judge determined that this was inconsistent with Mr. Abanukam’s letter of April 28, 1994, explaining why he had filed the documents late. (Finding 4; Mem. at 4; Resp. Exh. 1.)

Ms. West testified that she saw Mr. Abanukam on April 27, 1994, when he came to the OAH in the morning and had a conversation with Ms. Geer. Ms. West testified that she “never saw him offer any [paper] for filing.” (T. 195.)

On April 28, 1994, at 2:14 p.m., Mr. Abanukam presented for filing, at the OAH reception window, the following documents which were accepted and date stamped by an automatic machine:

In addition, Mr. Abanukam filed a letter later that day explaining why he had to file late. (Resp. Exh. 1.) Earlier in the day he had telephoned Ms. Klinkenberg at OAH, and asked her if “he could write a letter and have it put in his file about why he was filing late.” (T. 84.) When he filed the letter, he also attempted to explain to Ms. Klinkenberg why he was filing late. She testified that she told him she didn’t need to hear his explanation as she does not make the decision as to the timeliness of a filing, and is required to accept all filings.

Ms. West testified that it is her duty to enter data about the appeals which are filed, into a computer at OAH, and that she “probably was the one that entered the [employee’s] appeal into the computer.” Further, she recalled seeing the letter that the employee brought in on April 28, 1994. (T. 195; Exh. 1.) Ms. West also testified that she did not see two notices of appeal from the employee on April 28, 1994, and that she would have noticed that, as “that would have been very unusual.” (T. 195-96.)

On April 28, 1994, when the appeal documents described in Finding 4 reached the desk of Ms. Doolittle, the Court Administrator, for processing, Ms. Doolittle changed, in her handwriting, the date as stamped from April 28, 1994, to April 27, 1994. (Finding 6; Judgment Roll. See T. 62-63.) Ms. Doolittle testified that she was aware that April 27, 1994, was the last day for appeal in this matter and that she was aware that the pro se employee had visited OAH on April 27. She testified that she accordingly had assumed that the documents had been presented for filing on April 27, but had not been stamped until April 28, 1994. Ms. Doolittle further testified that she wanted to give the employee the benefit of any doubt. She had, however, not investigated further or consulted with any of the OAH clerical employees who might have accepted the filing. (Finding 6; T. 60-63.)

Ms. Doolittle and the other employees at OAH testified that the policy and procedure at OAH is to “process the paper, accept the appeal, and send out an acknowledgement of appeal.” OAH does not have jurisdiction to either accept or reject an appeal. Ms. Doolittle’s task is to ensure that the appeal papers are complete, signed, dated, and have a proof of service attached and that the filing fee has been paid. (T. 56.) Ms. Doolittle, who has worked at OAH for 13 years, testified that all of the secretaries and clerks have been trained in these procedures, and that they are told to accept all filings presented to them. She further testified that Ms. Geer had worked for OAH for at least three years, and Ms. Klinkenberg had worked there for six or seven years, and that both were trained in and familiar with the policy and procedure at OAH requiring them to accept any documents presented to them for filing. (T. 57-58.)

Ms. Geer testified that she would have accepted any filing from the employee on April 27, 1994, with or without the indigency affidavit, which could be filed later, but that Mr. Abanukam presented no appeal papers for filing on that date. Ms. West corroborated Ms. Geer’s testimony. (T. 160-62; 195.) Ms. Geer further testified that she referred the employee to Ms. Doolittle because he was pro se and needed an indigency affidavit for the transcript, a matter Ms. Doolittle always handled. (T. 108-11, 122.) The employee, on the other hand, testified that Ms. Geer had refused to accept his appeal papers on April 27. (T. 148-152.)

At the hearing on October 11, 1994, the compensation judge had the opportunity to hear the testimony of all of the witnesses and to assess their demeanor. He accepted the testimony of Ms. Doolittle, Ms. Geer, Ms. Klinkenberg, and Ms. West, and rejected the testimony of Mr. Abanukam as to whether Mr. Abanukam had effectively filed or attempted to file his appeal within 30 days of March 28, 1994. The compensation judge determined, based on the testimony and the evidence presented to him that Mr. Abanukam did not file or attempt to file his appeal on April 27, 1994, the 30th day, but rather he attempted to file such appeal on the 31st day thereafter, April 28, 1994, and that at no time on or before April 27, 1994, did any employee of the Office of Administrative Hearings refuse or fail to accept any documents presented by Mr. Abanukam for filing. (Findings 2, 3, 4, 7; Mem. at 3-4.)

The testimony of the employee conflicted with the testimony of the other witnesses in this case. The compensation judge’s determination thus necessarily rested principally on witness credibility. “Assessment of witness credibility is the unique function of the factfinder.” Tews v. George A. Hormel & Co., 430 N.W.2d 178, 41 W.C.D. 410 (Minn. 1988). It is not this court’s function to evaluate the credibility and probative value of witness’ testimony and to choose different inferences from the evidence than the compensation judge. Krotzer v. Browning-Ferris/Woodlake Sanitation Serv., 459 N.W.2d 509, 513, 43 W.C.D. 254, 261 (Minn. 1990). This court will not disturb a finding based on credibility of a witness unless there is clear evidence to the contrary. Even v. Kraft, Inc., 445 N.W.2d 831, 42 W.C.D. 220 (Minn. 1989). “Whether the evidence is documentary or oral, it is not the function of a reviewing court to try the facts anew.” Courtney, by Higdem v. City of Orono, 463 N.W.2d 514, 517 n. 2, 43 W.C.D. 571, 575 n. 2 (Minn. 1990). “Where more than one inference may reasonably be drawn from the evidence, the compensation judge’s findings shall be upheld.” Minn. Stat. § 176.421, subd. 1(3); Nord v. City of Cook, 360 N.W.2d 337, 37 W.C.D. 364 (Minn. 1985).

There is substantial evidence in the record, both oral and documentary, to support the compensation judge’s findings of fact. We, accordingly affirm the compensation judge’s finding that the employee’s appeal was not filed until April 28, 1994, the 31st day after the filing of Judge Nancy Olson’s findings and order of March 28, 1994.

A party must serve and file a notice of appeal within 30 days of the filing of the compensation judge’s Findings and Order. Minn. Stat. § 176.421, subd. 1; Minn. R. 9800.1600, subp. 1. Filing is complete upon receipt of the necessary documents at the office or department. Minn. Stat. § 176.275, subd. 1. Time limits for perfecting an appeal are jurisdictional. Where subject matter jurisdiction is lacking, this court cannot determine the merits of the case. Carpenter v. Woodvale, Inc., 400 N.W.2d 727, 39 W.C.D. 430 (Minn. 1987); Bjerga v. Maislin Transp., 400 N.W.2d 99, 30 W.C.D. 309 (Minn. 1987); Hemmesch v. Molitor, 328 N.W.2d 445, 35 W.C.D. 541 (Minn. 1983); Kearns v. Julette Originals Dress Co., 267 Minn. 278, 126 N.W.2d 266, 23 W.C.D. 127 (1964).

Having affirmed the compensation judge’s finding that the employee’s appeal was not filed until April 28, 1994, 31 days after the filing of Judge Nancy Olson’s findings and order on March 28, 1994, we conclude that the employee’s appeal in that matter was not timely filed, and this court, therefore, lacks jurisdiction to consider the employee’s appeal. We, accordingly, grant the employer and insurer’s motion to dismiss the employee’s appeal from the findings and order of Judge Nancy Olson, served and filed March 28, 1994.