My thought is that if the cam is advanced a tooth or more, even if the cylinder filling is not optimum, you will get plenty of compression pressure: the slow cranking speed would still allow decent cylinder filling and overlap is moved ahead of the start of the intake stroke of the piston so you don't get as much pulled back in via the exhaust, and it will compress well as the intake is closing so much earlier on the compression stroke. The high compression readings may actually be a sign of advanced cam timing. But, I have never run any tests on this, and so that is just a guess.
