You can install a blower on a 12.0:1 compression engine and it will work. But not as efficiently as it will with lower compression. It's very simple physics. You are trying to ram as much air and fuel into the cylinder as you can possibly get. The higher your compression the less fuel and air you can ram into the cylinder. You said you were getting 10 psi of boost.... If you had 11.0:1 compression, you weren't getting that kind of boost into the cylinder. It's impossible! You were getting some of the benifit but you were waisting most of it.

So if you are going to spend the money on a blower. Then do it right and take advantage of what the blower has to offer. Talk to anyone that builds blown engines and you will find that lower compression is the right way to go.