David and Jill Kehlenbrink v. Director of Revenue, 577 S.W.3d 798

In March 2017 David and Jill Kehlenbrink purchased a 2016 Dodge truck for $27,495 and titled it at a county license office; they paid sales tax after crediting $14,400 from two earlier sales (a 2006 Ford and a 2000 Kawasaki) and paid $1,095 in tax.
Within 180 days of the Dodge purchase they sold two additional vehicles (a 2008 Jeep and a 2013 Hyundai) and sought to apply those sale proceeds as additional trade‑in credits against the Dodge purchase.
A license‑office employee advised them they could credit the proceeds from the Jeep and Hyundai; using those credits the total trade‑in allowance exceeded the Dodge purchase price.
The Kehlenbrinks filed for a refund of the sales tax paid; the Director of Revenue denied the refund and the Kehlenbrinks appealed to the Administrative Hearing Commission (AHC).
The AHC found §144.025.1 ambiguous and allowed credit for multiple vehicle sales, awarding a full refund plus interest; the Director appealed to the Missouri Supreme Court.
The Supreme Court reviewed de novo the statutory interpretation and reversed the AHC, holding §144.025.1 permits credit for only one vehicle sale against the purchase price of a subsequent vehicle.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether §144.025.1 permits credit of proceeds from multiple prior vehicle sales against the purchase price of a newly purchased vehicle for sales‑tax calculation	Kehlenbrink: statute is ambiguous; AHC’s construction allowing multiple credits is permissible and agency/office practice supports it	Director: statutory text plainly limits the credit to one prior sale; singular references show legislative intent to allow only one trade‑in credit	Court: statute unambiguous; only one vehicle sale may be credited against the purchase price; AHC erred and decision reversed

McDonnell Douglas Corp. v. Dir. of Revenue, 945 S.W.2d 437 (Mo. banc 1997) (jurisdiction for revenue law construction)
Loren Cook Co. v. Dir. of Revenue, 414 S.W.3d 451 (Mo. banc 2013) (AHC statutory interpretations reviewed de novo)
Union Elec. Co. v. Dir. of Revenue, 425 S.W.3d 118 (Mo. banc 2014) (statutory words read in context for plain meaning)
State ex rel. Young v. Wood, 254 S.W.3d 871 (Mo. banc 2008) (primary rule: give effect to legislative intent reflected in plain language)
Wolff Shoe Co. v. Dir. of Revenue, 762 S.W.2d 29 (Mo. banc 1988) (statute’s terms plain to one of ordinary intelligence are unambiguous)
Kerperien v. Lumberman’s Mut. Cas. Co., 100 S.W.3d 778 (Mo. banc 2003) (rules of construction do not apply if statute is unambiguous)
Rumsfeld v. Padilla, 542 U.S. 426 (2004) (use of definite/indefinite articles can indicate singular intent)
State v. Campbell, 109 S.W. 706 (Mo. 1908) (definite article used to particularize)
State v. Nichols, 865 S.W.2d 435 (Mo. Ct. App. 1993) (plain meaning of “a” is singular)