For estimated assessment and final assessment purposes the cost of a local improvement shall be the actual cost as defined by ordinance. Allowances for engineering and superintendence as part of the actual cost shall be fixed by the Council by general ordinance from time to time. [May 17, 1918, new sec. 284-b; 1928 pub., sec. 284-b; am. Nov. 4, 1924; 1942 recod., sec. 9-106; rev. Nov. 8, 1966; am. May 20, 1986; am. Nov. 3, 1992.]