§ 440. Commissions and payment of expenses. The savings and loan bank may charge each member an annual commission, not to exceed one-half of one per centum, upon the outstanding bonds and notes issued in its behalf, provided, however, that the rate of commission in any year shall be the same on all outstanding obligations in respect to which a commission is charged; or in lieu of charging such commissions the expenses incurred on account of any such obligations may be charged to the member on whose behalf such obligations are issued.