Summary field not working--suspect key and reference field issue

So if inherently "Each of these tables has a field, Project Number", why not change the the Key field of the Project Forecasts table to be the Project number field.  

Then A:  either rebuild the relationship to Project Forecasts using that the Project Number on the Projects Forecasts,

or B:  if you already have a lot of lookup fields pulled down and on forms that you don't want to recreate, you can sort of cheat and change the field [Related Forecast] to be a formula field with a formula of [Project number]