Can any body write a formula to spread the services charge. For example

Annual charge is $12,000/ colum Jan to Dec monhtly 1000/- if start date is
16th Jan then Jan only 16 days and balance to go to colum Jan next year. I
use this formula:
=IF($A5<E$2,(IF($B5<E$2,0,(((IF($A5<E$2,(DAY(E$2)) ,((DAYS360($A5,E$2)+1)))/$C5*$D5))))),0).

formula works but if I take the start date as 16 Jan doesn't calculate for
16 days. Any help