(a) Increases. The PSB Surety must process Contract or bond amount increases within its allotment in the same manner as initial guaranteed bond issuances (see § 115.65(c)(1)). The Surety must present checks for additional fees due from the Principal and the Surety on any increases aggregating 25% of the original Contract or bond amount or $500,000, whichever is less, and attach such payments to the respective monthly bordereau. If the additional Principal's fee or Surety's fee is less than $250, such fee is not due until all unpaid increases in such fee aggregate at least $250.

(b) Decreases. If the Contract or bond amount is decreased, SBA will refund to the Principal a proportionate amount of the guarantee fee, and adjust SBA's Premium share accordingly in the ordinary course of business. No refund or adjustment will be made until the amounts to be refunded or rebated, respectively, aggregate at least $250.