Multiple Compiled Set Ids on RDLs for an Expenditure Item

Hi, I am diagnosing a custom report which uses the inv compiled-set-id from the RDL, combined with exp-org and expenditure-type, to get the  invoicing burden amounts by cost codes. The project invoicing is setup with invoice burden schedule.

For a given expenditure item I have more than one compiled set ids accross the RDLs. This is caused when the user compiles an existing burden schedule, which marks the expenditure items for revenue re-distribution. The issue I have is the compiled set id on the latest RDL returns the burdens but the earlier don't. Any clues why this would happen? thanks!