1991 mr2 turbo boost problem

I have a 1991 MR2 Turbo. The distributor went about two weeks ago and my mechanic replaced it with a remanufactured distributor without consulting me first. I had the turbo rebuilt this summer and after installing it, boost went all the way to the plus mark on the turbo guage. Now, since returning from the mechanic, boost only goes two-thirds of the way at best. Could this be related to a non-Toyota distributor? I set the timing at 10 degrees BTDC, so I am guessing that is not the problem. Could a different distributor warrant a timing change? Should it be replaced with a Toyota distributor?

Thanks to anyone who can help.