pro rata within a window different from a calendar year

[dvb_24]

Hi,

Assuming calendar years I have projected 7 years of sales and, taking into account a payment delay of 2 months, have calculated when those sales are cashed-in.

Then, I tried to calculate how much cash would get into a specific window of 12 months which doesn’t match a calendar year (i.e. 01-feb-yy to 31-jan-yy+1) but I’m stuck when trying to do the pro rata of the sales in the same manner I did with the calendar year.

Please see the file attached.

Any help is much appreciated.

[dvb_24]

Just to clarify, I try to get the sales cashed-in within a 12 months period NOT matching the calendar year.

For example, let's say that we have 6 months of sales in 2011, 12 months of sales in 2012 and the window starts on the 1-oct-2011. I would get 5 out of 6 months of sales from 2011 in that window because of the payment delay of 2 months. Then would get as well 7 out of 9 months from 2012 for the same reason.

I can do it logically but would like it to be dynamic for any window. Please help.