The investigation fee required by RCW 33.08.060 for submission in connection with applications to charter a new savings and loan association shall be two thousand five hundred dollars. In the event the actual costs of the investigation conducted with respect to a particular application are less than the amount of the fee, such difference between the fee and the actual costs submitted shall be refunded, provided that in no event shall more than one thousand five hundred dollars be refunded. For the purposes of this section, actual costs shall include travel and per diem expenses paid to division personnel in connection with the investigation.