EDT-Lose Fat , Keep Strength

I was just wondering if any one else had tried Coach Staley’s EDT-lose the fat, keep the strength program. I am currently in my second week of the program and i am enjoying it alot and i have already begun to experience some progress on the program. I have a couple of questions however.
How often should one change the core movements? My current core movements are squat, bench and row and i was thinking of changing these after 3 or 4 weeks to avoid reaching a plateau.
Also, is it ok to change the exercises in the two PR zone “circuits” after 3 weeks because i feel i may reach a plateau with them, aswell as just get a bit bored of them? Or should i stick with my exercise selections for longer, eg 6 weeks in order to see the full benefits of the program?
A little advice here would be much appreciated.