48 C.F.R. § 11.403 – Supplies or services.

(a) The contracting officer may express contract delivery or performance schedules in terms of—
1. (1) Specific calendar dates;
2. (2) Specific periods from the date of the contract; i.e., from the date of award or acceptance by the Government, or from the date shown as the effective date of the contract;
3. (3) Specific periods from the date of receipt by the contractor of the notice of award or acceptance by the Government (including notice by receipt of contract document executed by the Government); or
4. (4) Specific time for delivery after receipt by the contractor of each individual order issued under the contract, as in indefinite delivery type contracts and GSA schedules.
(b) The time specified for contract performance should not be curtailed to the prejudice of the contractor because of delay by the Government in giving notice of award.
(c) If the delivery schedule is based on the date of the contract, the contracting officer shall mail or otherwise furnish to the contractor the contract, notice of award, acceptance of proposal, or other contract document not later than the date of the contract.
(d) If the delivery schedule is based on the date the contractor receives the notice of award, or if the delivery schedule is expressed in terms of specific calendar dates on the assumption that the notice of award will be received by a specified date, the contracting officer shall send the contract, notice of award, acceptance of proposal, or other contract document by certified mail, return receipt requested, or by any other method that will provide evidence of the date of receipt.
(e) In invitations for bids, if the delivery schedule is based on the date of the contract, and a bid offers delivery based on the date the contractor receives the contract or notice of award, the contracting officer shall evaluate the bid by adding 5 calendar days (as representing the normal time for arrival through ordinary mail). If the contract or notice of award will be transmitted electronically, (1) the solicitation shall so state; and (2) the contracting officer shall evaluate delivery schedule based on the date of contract receipt or notice of award, by adding one working day. (The term “working day” excludes weekends and U.S. Federal holidays.) If the offered delivery date computed with mailing or transmittal time is later than the delivery date required by the invitation for bids, the bid shall be considered nonresponsive and rejected. If award is made, the delivery date will be the number of days offered in the bid after the contractor actually receives the notice of award.