25 USC 3413 - Administration of funds and overage

(a) Administration of funds 

(1) In general 
Program funds shall be administered in such a manner as to allow for a determination that funds from specific programs (or an amount equal to the amount attracted from each program) are spent on allowable activities authorized under such program.
(2) Separate records not required 
Nothing in this section shall be construed as requiring the tribe to maintain separate records tracing any services or activities conducted under its approved plan to the individual programs under which funds were authorized, nor shall the tribe be required to allocate expenditures among such individual programs.
(b) Overage 
All administrative costs may be commingled and participating Indian tribes shall be entitled to the full amount of such costs (under each program or departments regulations), and no overage shall be counted for Federal audit purposes, provided that the overage is used for the purposes provided for under this chapter.