By the way, I don't have call screening on, and my GV voicemail picks up my calls (forwards to cell and office at the same time).
It worked fine for over a year, and recently my cell phone VM was picking up too fast. I called VZW tech support -- and they lengthened the delay that it takes for the VZW VM to pick up, so that it always gets picked up by GV. Unless you call my cell directly, in which case VZW VM picks up.