If the department or any regional center intends to adopt any material change in policy which will have a direct effect upon the contract between the state and the regional center, the department or the regional center shall give at least 30 days’ notice of an intent to change policy, and, if necessary, the contract between the state and such regional center shall be amended. The department shall not require regional centers to provide or purchase any services beyond the level of the funding appropriation for such services. If the department should alter the rates of payments to providers, the regional center budget shall be adjusted accordingly.