Subject to the provisions of paragraph (2), after the closing of an account under section 1552(a) or 1555 of this title, obligations and adjustments to obligations that would have been properly chargeable to that account, both as to purpose and in amount, before closing and that are not otherwise chargeable to any current appropriation account of the agency may be charged to any current appropriation account of the agency available for the same purpose.

The total amount of charges to an account under paragraph (1) may not exceed an amount equal to 1 percent of the total appropriations for that account.

In the case of a fixed appropriation account with respect to which the period of availability for obligation has ended, if an obligation of funds from that account to provide funds for a program, project, or activity to cover amounts required for contract changes would cause the total amount of obligations from that appropriation during a fiscal year for contract changes for that program, project, or activity to exceed $4,000,000, the obligation may only be made if the obligation is approved by the head of the agency (or an officer of the agency within the Office of the head of the agency to whom the head of the agency has delegated the authority to approve such an obligation).

In this subsection, the term “contract change” means a change to a contract under which the contractor is required to perform additional work. Such term does not include adjustments to pay claims or increases under an escalation clause.

Obligations under this section may be paid without prior action of the Comptroller General.