Insurance Claims Payments to Health Care Providers; Prohibits payment adjudicators from downcoding health care services under certain circumstances; requires health insurers to ensure that their downcoding policies are updated & to ensure compliance with specified provisions on downcoding; authorizes investigations & actions against noncompliance; provides certain presumption in favor of physicians' determination regarding patients' diagnoses & service orders; provides calculations of interests on health insurers' nonpayment & underpayment due to downcoding; provides causes of action for health care providers; prohibits utilization review entities from implementing new requirements, restrictions, & changes on prior authorizations under certain circumstances; provides requirements for adverse determinations made by such entities on health care providers' claims; revises requirements & timeframes for responses from health insurers & HMOs to submitted claims.