(a) For all construction project agreements, advance payments shall be made annually or semiannually, at the Self-Governance Tribe's option. The initial payment shall include all contingency funding for the project or phase of the project to the extent that there are funds appropriated for that purpose.

(b) The amount of subsequent payments is based on the mutually agreeable project schedule reflecting:

(1) Work to be accomplished within the advance payment period,

(2) Work already accomplished, and

(3) Total prior payments for each annual or semiannual advance payment period.

(c) For lump sum, fixed price agreements, at the request of the Self-Governance Tribe, payments shall be based on an advance payment period measured as follows:

(1) One year; or

(2) Project Phase(e.g., planning, , design, construction.) If project phase is chosen as the payment period, the full amount of funds necessary to perform the work for that phase of the construction project agreement is payable in the initial advance payment. For multi-phase projects, the planning and design phases must be completed prior to the transfer of funds for the associated construction phase. The completion of the planning and design phases will include at least one opportunity for Secretarial approval in accordance with § 137.360.

(d) For the purposes of payment, Sanitation Facilities Construction Projects authorized pursuant to Pub. L. 86-121, are considered to be a single construction phase and are payable in a single lump sum advance payment in accordance with paragraph (c)(2) of this section.

(e) For all other construction project agreements, the amount of advance payments shall include the funds necessary to perform the work identified in the advance payment period of one year.

(f) Any agreement to advance funds under paragraphs (b), (c) or (d) of this section is subject to the availability of appropriations.

(g) (1) Initial advance payments are due within 10 days of the effective date of the construction project agreement; and

(2) subsequent payments are due:

(i) Within 10 days of apportionment for annual payments or

(ii) Within 10 days of the start date of the project phase for phase payments.