AAAaaahhhh Multiple Sheets Multiple Criteria

Please help, I have struggled with this for a week!! And I'm not sure how to explain it.

I have attached a spread sheet with three example sheets on it (in reality these are three seperate sheets)

If there are three mth 1's in the programme multiple units sheet I want it to go to the cashflow single unit sheet and multiply sales in mth 1 by three and then return the sum in cashflow multiple units.

But I want it to be able to do that for mths 2, 3 etc and return the total in the cashflow multiple units.

ie. apr 08 would have 3 lots of sales month 1, plus 3 lots of mth 2 sales
then on the deposits line it would have 3 lots of deposits month 1 plus 3 lots of mth 2 deposits.

I'm not sure if I'm making much sense now because I've gone round in circles so much I'm getting dizzy. I feel that sumproduct may be the answer but have not used it before.

Hopefully the spread sheet will clarify what I'm trying to say (I have attached it but can't see it on the preview?). But any questions for clarification or suggestions would be HUGELY appreciated.

Sorry I'm new to this and when I tried to attach as excel it didn't allow it and only showed me other attachment forms, this was the closest I could get.

Ok here goes! You're already my hero, now if you can just solve my other problem

In my example there are 8 units that commence construction at different times, mth1 being the first month of activity (cost) and month 5 have cost and sales.

Each unit has a spend pattern as per the cashflow per unit. I want the cashflow for multiple units to be able to pick up the cost or sales in total for all the units in the correct months.

Hope this makes it clearer I'm better with numbers than I am with explanations.

Thanks for looking and your time.

Pleeeeeeeease does anyone have any ideas?

I am wondering whether a sumproduct and match formulas together might do it, but I haven't used these before and don't know how to structure it?

Does anyone have any ideas where else I can go to get a solution for this. I feel that I'm being quite dense now and can't see the obvious solution!

Thanks for your help