Adding Intercompany_Yes to existing FCCS Accounts that historically has not had this attribute

We want few accounts that historically did not have the attribute Intercompany_Yes to now have that attribute. Previously the non-intercompany mapped to FCCS_No Intercompany.

After testing in fccs-test (QA) environment we found that some account/entity combinations populate a zero in YTD and the Periodic is correctly reversing the prior month's YTD. While other account/entity combinations are putting a null in YTD and so the previous month FCCS_No Intercompany is carrying forward to the new month. We cannot figure out why it is populating a zero (which we would want) while other times it is populating a null in the current YTD month.