Hello,
You can use tr. ST05 to trace tables which is used in tr. fmavcr01 or fmrp_rw_budcon.
Start ST05 -> Click "Activate trance" button.
Then Start you transaction and work with it.
Then get back to ST05 -> Click "Deactivate trace" and then click "Display trace"
there can be new trace and then you can find tables in column "Objec name", which were use for your transaction.
And there can be used old trace - then you have to look throughn "Statement" column lines like this TABNAME = 'FMAVC_S_BO_ANNUAL_TOTALS'