A carrier may not reimburse a health care practitioner in an amount less than the sum or rate negotiated in the carrier’s provider contract with the health care practitioner. This section does not prohibit a carrier from providing bonuses or other incentive-based compensation to a health care practitioners. A carrier that compensates health care practitioners wholly or partly on a capitated basis may not retain any capitated fee attributable to an enrollee or covered person during an enrollee’s or covered person’s contract year.