Warranty work performed by the dealer shall be compensated in accordance with the reasonable and customary amount of time required to complete the work, expressed in hours and fractions of hours, multiplied by the dealer's established customer hourly retail labor rate for non-warranty repair work, which must have previously been made known to the supplier. Parts used in warranty repair work shall be reimbursed at the current net parts cost plus 15 percent.
Tex. Bus. and Comm. Code § 57.255