(a) If a State has knowledge that an estimate does not reasonably correspond to the State's cash needs for a Federal assistance program or program component, or if a Federal assistance program undergoes operational changes that may affect cash needs, the State must immediately notify us in writing. We and the State will amend the funding technique provisions in the Treasury-State agreement or take other mutually agreed upon corrective action.

(b) When estimates are properly updated and applied, a State or Federal interest liability may or may not accrue, depending on the terms of the Treasury-State agreement.

(c) We may require a State to justify in writing that it is not feasible to use a more efficient basis for determining the amount of funds to be transferred under the Federal assistance program or program component to which an estimate is applied. We may prescribe requirements for certifying the reasonableness of an estimate.