hmmm, to be honest, I couldnt tell you. Its most likely because you feel the need to jump forwards therefore messing up your rotation. I remeber back in the day, to learn corks off of tramp into the foam pit, i would go for the five, but steeze it out as hard as you could. Im talking like full on dub safety, style leaking out of your pores. This position allowed me to alter my axis easier becasue of my compressed shape. Ease into it, dont go for the straight up cork, just go for the tiny off axisness (pretty steezy in my opinion) and from there just evolve into the cork. Maybe go to a bigger pool with a bigger diving board. You could also go straiht for the over flip, and work backwards from there.