Since you can feel the song, have you ran thru the song in the ACW while tapping the F8 key on the first beat of each measure? This sets where 1 is in each measure; you can see the ACW adjusting in realtime.

Sometimes this can guide the ACW along in the tempo map, especially if the tempo changes quite a bit throughout the song. However, if it changes for only 1 beat, this will not solve the problem .. as that measure will be adjusted and not just the note. However, this may get you closer to being able to change the time sig for that one measure

I do not work here, but the benefits are still awesome
Make your sound your own!