Multiple criteria if statement

[braydon16]

I have a number of units, a rate per month these units are absorbed, and a cost per unit of absorption; not to mention a date function coinciding with them. I need to subtract the units at the given rate per month beginning with the specified first month. I need to use up no more than the total number of units.

At the moment, the cells under each date is as follows:

=IF(EOMONTH(H$1,0)>=EOMONTH($E2,0),$D2*$F2,0)

[macquarl]

I managed to move this one along a little...but it still needs help.

by adding two columns (one that divides the number of unit by the rate) and another that adds the start date and the newly created units/rate calc) I was able to estimate the ending date. By modifying the IF statement so it looks like this :
=IF(EOMONTH(I$1,0)>=EOMONTH($E2,0),IF(EOMONTH(I$1,0)<=EOMONTH($H2,0),$D2*$F2,0),0)
It will only calculate the between the months in the start and end month columns else it will put in a zero.

The only problem that is left is that there isn't an even amount of numbers so the final months calculation is off by whatever the decimal amount is.

Sorry I couldn't completely solve it but at least here is something to work with.

[braydon16]

This has seemed to be a real challenge. Anyone with some insight would be greatly appreciated.