Checking bell housing alignment?

[RBR]

I have a new tremec tko600 kit it came with all the stuff. I checked my bell housing alignment and was past the 0.005 tolerance. I then checked my old bell housing and it was with in spec of 0.005 . Is it comon that a new bellhousing will be off & have to use off set dowels? My old bellhousing won't fit, and my new one is just the cast gm one that comes with the kit.