I have converted a previous data base in FMP 4 to the v11 and am using a trial version until our new software / hardware arrives. I am running on a Dell laptop with xp installed, and our new system will be MAC. My issue is that in a business application, I have created a receivables summary field that is a lookup to separate from our actual contract table. The calculation for the Balace due summary is not correctly calculation from Payment Summary and the Project Total fields I have imported. It functions correctly with one payment record but is incorrect when multiple payments are applied. I am attaching a "sandbox" version of the file I have been playing with, but so far I have not been able to resolve the issue. Any suggestions?