i'm in the same boat as you. i always thought that I was chipping correctly, then learned a couple of things that made big improvements in the consistency of my chipping stroke:
move closer to the ball when chipping so that the club shaft is more vertical
play the ball further back in your stance. depending on the lie, can be anywhere from just in front of right foot to a couple of inches behind the right foot
of course, there's the other stuff (grip down, weight forward, accelerate, etc), but these 2 adjustments were huge.