24 CFR 241.520: Fees on increases.

(a) Increase in firm commitment prior to endorsement. An application filed prior to initial endorsement (or prior to endorsement in a case involving insurance upon completion), for an increase in the amount of an outstanding firm commitment shall be accompanied by a combined additional application and commitment fee. This combined additional fee shall be in an amount which will aggregate $3 per thousand dollars of the amount of the requested increase. if an inspection fee was required in the original commitment, an additional inspection fee shall be paid in an amount computed at the same dollar rate per thousand dollars of the amount of increase in commitment as was used for the inspection fee required in the original commitment. When insurance of advances is involved, the additional inspection fee shall be paid at time of initial endorsement. When insurance upon completion is involved, the additional inspection fee shall be paid prior to the date construction is begun or if construction has begun, it shall be paid with the application for increase.

(b) Increase in loan between initial and final endorsement. Upon an application, filed between initial and final endorsement, for an increase in the amount of the loan, either by amendment or by substitution of a new loan, a combined additional application and commitment fee shall accompany the application. This combined additional fee shall be in an amount which will aggregate $3 per thousand dollars of the amount of the increase requested. If an inspection fee was required in the original commitment, an additional inspection fee shall accompany the application in an amount not to exceed $5 per thousand dollars of the amount of the increase requested.