Hi Sajid,
You can change your derivation rules in FMDERIVE, But in the middle of the financial year you have a challenge like already transactional data was posted with old fund and fund center, So if you change now your system will be mess up and leads to inacurate reporting.
Its better to do in the yearend, and also please take care about yout commitmnets, after yaer end i hope you have less probability for errors, if any also you can do FM reassignmnets.
I hope It is clear.
Regards,
Ravi
