STs are underachieving in general.

Have you maybe been much stronger previous seasons than the opponents?
I have noticed that in such games where you ruin your oppo, ST gets a good rating and scores

When teams are almost equal, ST will hardly score when playing from flanks. I get in such games my goals from AM as well.
I get most goals from ST from free kicks + penalties.

STs have a better rating when playing from middle without AM though