30 yards better than 20?

I've tried uncomfortable pit blinds that look like a stump pile and have come to believe the deer are as afraid of the bait as of any blind I might come up with. Now I hunt from a home made box blind and sometimes from a pop up over bait at 30 yards. I'm now thinking about moving the bait in to 20 yards, figuring deer sometimes hesitate/hang back from the bait and if they're within 30 yards I got 'em. My concern is, is 20 yards too close to an obvious ground blind?
Would appreciate any opinions.