Hi Donny,
I can't comment on songbook functions, but as far as I'm aware ( unless something has changed in pa4x) an sts is assigned to a particular variation ie
Sts1 vari 1. Sts 2 vari 2. May not be the case for songbook.

Don't know if it will make any difference but maybe the

Style to keyboard set button might be doing something that you don' t want.

There are 3 settings. Off, on ( solid red) and flashing. All 3 have different purposes in style play mode.

Maybe try changing the setting.