Here is the table and i need to calculate the amount based upon the days.

cell For days 8 to 14 cell A shows 10000, for days 15 to 21 cell A shows B+C and after 21 days cell A shows B+C+D. After 28 days with every passing week it should add cell D values additionally. for example after 28 days calculation should be B+C+D+D and so on.
Here is the formula I'm using.
=IF(AND($E$10>7,$E$10<=14),$B$10,IF(AND($E$10>14,$E$10<=21),SUM($B$10:$C$10),IF($E$10>21,SUM($B$10:$D$10),"")))
need help to calculate values after 4 weeks, on every passing week value of cell D should be added.