I am quite good at math, but I already know what you mean because it happened to me. In 9th grade, I switch to a rigorous private school and went straight into Algebra II and struggled because of gaps and lack of mastery from previous grades. But my son is solid (except for a couple of random asynchronous things that may never rectify and may talk longer for him to master.) I'm not talking about skipping anything...just going over certain things faster if he has them down and wonder if another program could be better for hat. Both my son and I are really into "box checking" and routine so not being tied to a program would be hard! Lol!