If I am reading this right you are only doing one top set followed by one back off set for your squat? Doesn't seem like enough volume to keep things going. I would just add another back off set (probably at closer to 85-90%) and see what kind of mileage you can get out of that.
Singles across work pretty well but again you will need some volume work in there as well.
I like rotating rep ranges once running out out has been complete.