Extreme C5

I have a 1998, A4 with a procharger, LG Pro Headers, Corsa catback and other minor mods....444rwhp. I blew out my transmision after installing the procharger which was expected since I have over 75,000 miles
I went with a Stage 5 trans from RPM Transmissions and I upgraded to 3:42 gears with a 3000 stall.
When I got the car back from the shop, it was shifting harder than usual at about 42mph which I believe is between 3 and 4 gear. I can't remember exactly what the installer told me but he said it was normal for 97' and 98' vettes to do this with a complete trans swap. I told him it was annoying as hell because that is a very common speed and it happens frequently. He said he could change my shift points and make it happen at 55mph so it is less frequent, which he did but it is still annoying.
All I want to know is is this normal? What is causing it? How do I get it fixed?
Thank you in advance for any advice you can give.

Vetteman Jack

Why not call RPM Transmissions and ask them about this. I'm sure they can give you the straight answer.