So, did you created all sound FX in the Psycho scene yourself or put just the scream in there, I'm a little confused on that from your description?
The music however, I thought it worked perfectly and was building up the right amount of tension up to when he begins to stab her. Personally I would have wished for a change there, because at this point the theme became repetitive which robbed the scene of it's possible impact. Also the music worked itself to much in the foreground, distracting the viewer from what's actually important in the scene.
"Let me tell you this: if you meet a loner, no matter what they tell you, it’s not because they enjoy solitude.
It’s because they have tried to blend into the world before, and people continue to disappoint them."