Regarding the post-processing program for accounting document archiving (FI_DOCUMNT) in an ECC envir

[#1]

Is the post-processing program (FI_DOCUMNT_PST) for the accounting document archive (FI_DOCUMNT) mandatory in an ECC environment? If it is mandatory, please also explain why post-processing is required.
My understanding is that the post-processing program deletes data from backup tables (such as BSAS_BCK); since BSAS_BCK does not exist in an ECC environment, I assume the post-processing program does not need to be executed.