I am trying to build a spreadsheet that calculates cashflow forecasts
for contingency based fee billing.
Basically a completed engagement would be capitalized upon over "N"
years and more importantly billed in quarters.

If I finish an engagement in month one, I will see my first cheque in
month 2 and the rest of the cheques in months 5/8/11/14/17/20/23 based
on a two year agreement, but some are 1 year and some are 3 year.

The problem is I want to plug in a variable number of engagements (at
variable amounts and durations) for each month and then have the
spreadsheet calculate the quarterly amount and put it in the proper
collection month while taking into consideration the compounding
effect of multiple engagements. e.g. if I do one engagement in month 1
and then 1 in month 4, in month 5 I am receiving two payments, so on
and so forth.

I started working on this but I am ending up creating a massive sheet
and I am sure there is a better way to do this. Any help would be
greatly appreciated.

B