((a)) The head of an agency or major organizational unit within an agency may place an order with a major organizational unit within the same agency or another agency for goods or services if—

((1)) amounts are available;

((2)) the head of the ordering agency or unit decides the order is in the best interest of the United States Government;

((3)) the agency or unit to fill the order is able to provide or get by contract the ordered goods or services; and

((4)) the head of the agency decides ordered goods or services cannot be provided by contract as conveniently or cheaply by a commercial enterprise.

((b)) Payment shall be made promptly by check on the written request of the agency or unit filling the order. Payment may be in advance or on providing the goods or services ordered and shall be for any part of the estimated or actual cost as determined by the agency or unit filling the order. A bill submitted or a request for payment is not subject to audit or certification in advance of payment. Proper adjustment of amounts paid in advance shall be made as agreed to by the heads of the agencies or units on the basis of the actual cost of goods or services provided.

((c)) A condition or limitation applicable to amounts for procurement of an agency or unit placing an order or making a contract under this section applies to the placing of the order or the making of the contract.

((d)) An order placed or agreement made under this section obligates an appropriation of the ordering agency or unit. The amount obligated is deobligated to the extent that the agency or unit filling the order has not incurred obligations, before the end of the period of availability of the appropriation, in—

((1)) providing goods or services; or

((2)) making an authorized contract with another person to provide the requested goods or services.

((e)) This section does not—

((1)) authorize orders to be placed for goods or services to be provided by convict labor; or

((2)) affect other laws about working funds.