No bank shall enter or at any time carry on its books any of its assets at a valuation exceeding their actual cost to the bank; nor shall the value of any of its assets be increased on the books of the bank without the written consent of the director. Additional charges, delinquency charges and other similar charges on consumer credit transactions permitted by and made in compliance with the Idaho Credit Code and added to the principal balance of the loan, shall not come within the prohibition of this section.