This is an issue with customs. You can find reports on reddit as of 40 days ago so it seems like its not worked since launch.
The coach suggestions will show plays you put in the gameplan in my testing, but will not rotate through all of the plays for a situation - and seem to totally ignore the rating you actually gave plays for frequency. HOPE THIS IS FIXED because i struggle with adhd and need a gameplan to enjoy offense. Outside games i can pretty easily work out when i want to run what but during a game with seconds to choose, i struggle pretty mightily.