Each State that enters into an agreement with the Secretary for Federal Administration of a State's mandatory and/or optional supplementary payments must pay the Social Security Administration (SSA) an amount sufficient to cover the State's liability for these expenditures. In addition, State liability will include a fee to cover the cost to the Federal government for administering the State's supplementary payments. Fees for subsequent years will be the applicable rate in the preceding fiscal year, increased by the percentage. If any, by which the Consumer Price Index for the month of June of the calendar year of the increase exceeds the Consumer Price Index for the month of June in the preceding calendar year, and rounded to the nearest whole cent, or such different rate as the Commissioner determines is appropriate for the State.

See the link below for administrations fee schedule website.

Fees for Administration of State Supplementary Payments

SSA determines state liability monthly under the provisions of the State supplementation agreement.

1. a. 

   Each month, the State is required to transfer funds to SSA to cover its estimated monthly liability. Electronic transfer of funds is the preferred method of funds transfer (see SI 02901.510 B).

2. b. 

   Transfer of funds are required to be made timely to ensure that monies are deposited to SSA on the fifth business day after payments are to be made to the recipients. States subject to the provisions of the Cash Management Improvement Act of 1990, will be charged an interest penalty for late payments.