I have a list of contracts with daily volumes and dates which start and end
at various points over months/years organized in rows. Next to the this I
have columns for every calendar month moving years into the future. What I
need to do is have a formula to return the average contract volume applicable
to every given calendar month across the months.

ie. If the contract was for 30 units per day and the contract date started
Nov 30/07 then the average daily volume for Nov/07 would be 1 unit.

Any help will be greatly appreciated.