It can lose oil through the snout seal OR through the rotor seals. Many places don't replace the rotor bearings or seals when they rebuild these superchargers. I would advise making sure if that was done or not. If not, it's probably the cause. You could take the SC hat off and look for black residue on the inside front of the case to see if you have much leakage there.
You could also have a bad seal between the snout and case, but I assume that you would have figured that out already if that was the problem.