I had a subfloor put on an old subfloor. Now I am told the job that was done by my contractor did not level the floor. The jog is horrendous I was told and I was told to take the contractor to court. He put strapping in and tried to shim up the floor. Now my question should he have put another subfloor shimmed up on an old plywood subfloor or should the old subfloor have been taken up and a new one put down? I now have an incorrect amount of screws put down and to many voids and now there is of course flex in the floor and the flooring guy says he can't put down the floor because of the flex. Should you ever put one subfloor on top of another?