this may seem a bit long but its worth it.......
set the tempo sync to its lowest/fastest setting (or the lowest setting you would use anyway)
lets say its 1/64..... now make an automation clip for it...... hover the mouse over the adjustable point in the automation clip and look at the little grey area under the file menu in FL.... it should say the value (in %)..... write the setting (1/64) and value down on a piece of paper then delete the auto clip
next change the setting to the next synced time (1/32 maybe??) and repeat the first step....... and keep doing this for all the sync times you want to use
yes, its long, but write them down and keep them safe...... you now have know the values and can refer to them in future tracks when you wish to automate the sync time with that filter again...... i write mine in a book....... ive done it for a few plugins now....... i'll share them if your interested