Figured out a solution. Instead of bringing it into the Forecast table, I was able to bring "Maximum Forecast Date" into the Projects table and sum everything there. It means I can only sum the revenue for the most recently created forecast, and lose some visibility to the revenue for old forecast months, but maybe I can just export the report once a month to a drive. I am also thinking about doing some sort of Record ID#-1 relationship so I could sum revenue for the past few forecasts. Either way, thanks for your help! I'm sure I'll use some of these concepts in the future.
