A public agency that has begun implementing an approved project may impose a PFC until—
The charge expiration date is reached;
The total PFC revenue collected plus interest earned thereon equals the allowable cost of the approved project;
The authority to collect the PFC is terminated by the Administrator under subpart E of this part; or
The public agency is determined by the Administrator to be in violation of 49 U.S.C. 47524 and 47526, and the authority to collect the PFC is terminated under that statute's implementing regulations under this title.