Bowling spin: ball turning opposite direction to expectation

[Risc_Terilia]

I used to bowl off spin and was getting a decent amount of turn with two fingers together at the top of the ball. I recently changed my grip to try to improve accuracy to the grip below, pushing my index finger along the seam (and using wrist movement) to get the spin as per the arrow as my thump comes off the ball.

The odd thing is that this ball very definitely turns to off rather than turning to leg and I can't think why that would be happening. As it happens I'm quite happy with it doing that but I'm just worried that it will stop doing that and I won't know why. Can anyone help explain this?



Thanks