Yes you can lose some boost through the snout. Mine is overdriven about 23% making about 17 pounds of boost max and had a cronic problem with the snout seal leaking and spraying the entire engine compartment with a mist of supercharger oil. When this happened I would lose about 1-1/2 to 2 psi.
Apparently the seal and needle bearings that seperate the gear oil case from the rotors when worn will allow boost to enter the gear oil case and trap it there. Even after sitting for several days there was enough air pressure trapped to shoot the fill plug half way across my garage. I even experimented with a pressure relief valve and standpipe screwed into the fill hole to allow any pressure over 5 psi to excape. This turned into an even bigger leak, because once I provided a path for the boost to go, it leaked even more and took the oil with it, drenching the engine bad enough to make the headers smoke when the oil drops hit them.
I nearly cured the problem by installing a newer set of rotor and gears, but after a few months the case pressure began to push on the snout seal hard enough, that the flimsy retaining ring would be pushed out of the retaining groove and the seal would then move forward enough that the back side of the pulley wore a hole in it and allowed oil to spray everywhere.
Charles Warner supplied me with a heavy duty snap ring to replace the stock flimsy bent wire that keeps the seal in place. That seems to be holding up for the last 6 months, but it's still trapping case pressure high enough to launch the fill plug.
David