Hi Atif,
I just tested FMCT for a PR with account assignment category K without any chained documents. Yes, FMIOI was updated with the new commitment item. When I went ahead to create a PO with reference to this PR, yes, system was still deriving the CI based on the FMDERIVE. Only after I switched off the 'overwrite with new value' indicator in FMDERIVE, system was using the CI from the PR.
However, I also found this has nothing to do with PR changes. Even with a brand new PR, the system behaves the same way as above described. The FM account assignment inheritance starts only from GR onwards.
Regards,
Ming