This opinion will be unpublished and
may not be cited except as provided by
Minn. Stat. § 480A.08, subd. 3 (1998).
STATE OF MINNESOTA
IN COURT OF APPEALS
In Re the Marriage of:
Beth Ann De La Hunt, f/k/a
Beth Ann Janssen, petitioner,
David Anthony Janssen,
Filed October 10, 2000
Ramsey County District Court
File No. DM26798
Barbara J. May, 4105 North Lexington Avenue, Suite 310, Arden Hills, MN 55126 (for appellant)
Dan C. O’Connell, Michael D. Wentzell, Collins, Buckley, Sauntry & Haugh, P.L.L.P., W-1100 First National Bank Building, St. Paul, MN 55101-1379 (for respondent)
Considered and decided by Toussaint, Chief Judge, Amundson, Judge, and Parker, Judge.*
U N P U B L I S H E D O P I N I O N
TOUSSAINT, Chief Judge
In this child-support modification proceeding, appellant Beth De La Hunt alleges that the district court failed to apply the correct statute in determining respondent David Janssen’s income from self-employment and abused its discretion by denying her request for child-support during the summer months. We reverse and remand.
Whether a source of funds is income for support purposes is a legal question reviewed de novo. Sherburne County Soc. Servs. v. Riedle, 481 N.W.2d 111, 112 (Minn. App. 1992). Respondent is the sole shareholder of a closely held, subchapter S corporation that is his sole source of income. Appellant argues that the district court erred by failing to apply the statutory formula for determining a self-employed obligor’s income for child-support purposes. Under the statutory formula, (a) income from self-employment is “gross receipts minus ordinary and necessary business expenses[;]” (b) “[o]rdinary and necessary expenses” for purposes of determing income are not identical to deductions allowed by the Internal Revenue Service (IRS) for determining income tax; (c) the district court may reject any claimed expense deemed “inappropriate for determining income for purposes of child support[;]” and (d) if an expense is challenged, the support obligor has the burden of proving the “ordinary and necessary” nature of the challenged expense. Minn. Stat. § 518.551, subd. 5b(f) (Supp. 1999).
Respondent’s accountant testified to respondent’s gross and net income and stated that respondent takes “virtually all of the cash out of the business that he is able to without causing adverse consequences to the business.” Despite the accountant’s testimony indicating that he did not use the gross receipts of respondent’s solely owned corporation to estimate respondent’s income, the district court relied on this testimony in finding respondent’s income. Thus, the district court did not rely on the statutory formula to determine respondent’s net monthly income for support purposes. We reverse the finding of respondent’s income and remand for the district court to reconsider the question under the relevant law.
The district court apparently denied appellant’s request for support during the summer because the parties had stipulated to what they referred to as joint physical custody and because there had been no motion to modify that aspect of the judgment. Whether to modify child support is discretionary with the district court. Kuronen v. Kuronen, 499 N.W.2d 51, 53 (Minn. App. 1993), review denied (Minn. June 22, 1993). A district court abuses its discretion when it improperly applies the law to the facts. Ver Kuilen v. Ver Kuilen, 578 N.W.2d 790, 792 (Minn. App. 1998). Also, the designation of a custodial arrangement is not dispositive regarding the existence and amount of a support obligation. See Tweeton v. Tweeton, 560 N.W.2d 746, 748 (Minn. App. 1997) (rejecting argument that label of stipulated custody arrangement governs support calculation and holding that “the substance of the arrangement” governs support requests), review denied (Minn. May 28, 1997). Here, there is no indication that the district court based its denial of appellant’s motion on substance rather than the label of the parties’ custodial arrangement. Moreover, the non-existent summer support obligation is below the guideline amount and the district court found a substantial change in circumstances meriting the increase of respondent’s support obligation for the other nine months of the year. Cf. Compart v. Compart, 417 N.W.2d 658, 662 (Minn. App. 1988) (stating that where support obligation was less than half guideline amount, “almost any change in circumstances would have been substantial”). On remand, the district court shall re-evaluate the propriety of awarding appellant support during the summer in light of the substance of the summer custodial arrangement and fully explain its decision.
On remand, whether to reopen the record is discretionary with the district court. We express no opinion on how to decide the remanded issues.
Reversed and remanded.
* Retired judge of the Minnesota Court of Appeals, serving by appointment pursuant to Minn. Const. art. VI, § 10.
 Absent something novel or questionable about application of the relevant law, an appellate court has an obligation to decide cases in a manner consistent with existing law. State v. Hannuksela, 452 N.W.2d 668, 673 n.7 (Minn. 1990); see Greenbush State Bank v. Stephens, 463 N.W.2d 303, 306 n.1 (Minn. App. 1990) (applying Hannuksela in a civil case), review denied (Minn. Feb. 4, 1991). There is nothing novel or questionable about applying Minn. Stat. § 518.551, subd. 5b(f).