(a) The executive commissioner shall set the payment rates for ICF-IID facilities at least annually.
(b) The executive commissioner shall adopt by rule the methodology used by the executive commissioner in setting payment rates for ICF-IID facilities. The methodology shall clearly define the procedures and methods used in projecting the costs of economic and efficient facilities and the procedures and methods used in setting payment rates that reasonably reimburse facilities at each level of care and in each class of providers, including size categories.

(c) The executive commissioner shall ensure that the methodology used in projecting costs and setting payment rates and its implementation is the same for state-operated ICF-IID facilities and for private ICF-IID facilities. Methods used to project costs, including those involving the handling of gifts, grants, and donations, upper limits on facility and administrative costs, occupancy adjustments, and in assessing the cost impact of new or revised requirements, must be the same for state-operated and private facilities.
(d) To the extent allowed by federal law, any differences in methodology or its implementation between state-operated facilities and private facilities must be stated explicitly in the rule, must be related to actual differences in the nature of the expenses incurred by the class of providers, including size categories, and must not favor state-operated facilities in setting payment rates. When the proposed rule or amendments to the rule are published for public comment, the executive commissioner must certify that any differences in methodology between classes of providers, including size categories, are necessitated by cost structure and will not favor state-operated facilities in the setting of payment rates.