I'm still learning the ropes here - hopefully a posting link will show up. This is a definitive posting regarding VCV & modulator settings - w/ great pics. If I post this correctly, this should take you to Dieseldan's posting regarding his VCV testing.
The answer is yes, there is a leak occuring with the VCV - it's just a question of how fast. Particularly if you test with the engine stopped and no throttle, there should not be a very fast leak, IIRC
http://www.peachparts.com/shopforum/showthread.php?p=1348968
Click Me!