The department of accounts and finances shall establish and maintain a fund to be designated fund to finance intersections. Immediately upon the completion of the work of any contract for improvements herein authorized, the city engineer shall carefully estimate and correctly certify to the city council the exact amount which has been spent in the performance of such contract for proper intersection purposes. The council shall at once carefully examine such certification and either approve or reject the amount so certified. If it is rejected, further certifications shall be required until a proper amount has been certified, which shall be approved. As soon as approved, the department of accounts and finances shall charge the special assessment sinking fund with the full amount as approved and shall credit the fund to finance intersections with a like amount. Just before each interest payment date an account shall be correctly and exactly stated between said funds so as to apportion as properly and exactly as possible the respective interest charge against each fund. The two funds above mentioned shall be continuously kept and maintained so that the fund to finance intersections will show exactly or approximately the total amount of bonds which has been devoted to the payment of intersection charges.