You're very welcome, John. Jim's right, as the vacuum gets lower, the power boost is reduced as well. It's the pressure difference between what your engine makes for vacuum and the local atmospheric pressure that determines how much assist you get.

However, I installed a used booster on one of my other cars, and ended up with way too much boost! The brakes were extremely touchy and almost impossible to use properly. I installed yet another booster and the brakes were back to normal. I haven't run across that problem since. I doubt that the booster was built differently regardless of the origin, so I think the valve that opens when you press on the pedal was probably defective and opening too easily.