If revenue under a contract for the provision of a rate-based service exceeds allowable costs incurred in the contract period, the contract shall allow the provider to retain from the surplus up to 5 percent of the revenue received under the contract unless a uniform rate is established by rule under subd. 5., in which case the contract shall allow the provider to retain the uniform percentage rate established by the rule. The retained surplus is the property of the provider.

If on December 31 of any year the provider’s accumulated surplus from all contract periods ending during that year for a rate-based service exceeds the allowable retention rate under subd. 1., the provider shall provide written notice of that excess to all purchasers of the rate-based service. Upon the written request of such a purchaser received no later than 6 months after the date of the notice, the provider shall refund the purchaser’s proportional share of that excess. If the department determines based on an audit or fiscal review that the amount of the excess identified by the provider was incorrect, the department may seek to recover funds after the 6-month period has expired. The department shall commence any audit or fiscal review under this subdivision within 6 years after the end of the contract period.

The department, in consultation with the department of health services and the department of corrections, shall promulgate rules to implement this subsection including all of the following: a. Requiring that contracts for rate-based services under this subsection allow a provider to retain from any surplus revenue up to 5 percent of the total revenue received under the contract, or a different percentage rate determined by the department. The percentage rate established under this subd. 5. a. shall apply uniformly to all rate-based service contracts under this subsection. b. Establishing a procedure for reviewing rate-based service contracts to determine whether a contract complies with the provisions of this subsection.