I'm not so sure the service he's currently receiving is that much better than he got under Sheehan last season to be honest, although as Phil points out, it's far better than he got under Williams.
Sheehan gave him a good run of starts when he took over and the results weren't great for Vip. I think, as others have said, that the big difference this year is confidence. He scored off the bench against Watford and instead of then drawing a blank in the next game as often happened after he scored last season, he spanked in that beauty against Plymouth. That's got to have given him more confidence, then the goals kept coming.
It's not as if we're providing him with lots of chances, as the goals against Plymouth and Hull were mostly of his own making.
It's hard to imagine him now having a game like he did against Plymouth at home last season, where we did give him good chances and he missed them all.