A health insurance policy shall permit and apply a prorated daily cost-sharing rate to maintenance medications that are dispensed by a pharmacy as a partial supply if the pharmacist or prescriber determines the fill or refill to be in the best interest of the patient and the patient requests or agrees to a partial supply for the purpose of medication synchronization. The fill or refill under this section shall be limited to three times per year for each maintenance medication for a covered individual. For each clinically necessary synchronization thereafter, approval may be required at the discretion of the health insurance policy.