All Medicare, Medicaid, or other program income earned by a Self-Governance Tribe shall be treated as supplemental funding to that negotiated in the funding agreement. The Self-Governance Tribe may retain all such income and expend such funds in the current year or in future years except to the extent that the Indian Health Care Improvement Act (25 U.S.C. 1601 et seq.) provides otherwise for Medicare and Medicaid receipts. Such funds shall not result in any offset or reduction in the amount of funds the Self-Governance Tribe is authorized to receive under its funding agreement in the year the program income is received or for any subsequent fiscal year.