Actually, what you describe is a pretty typical house pattern, I call it adult bumper bowling. The dry on the outside kicks balls back towards the pocket, and the oil in the middle holds tugged shots from breaking so they slam into the pocket. The way your playing it, your ignoring the dry which forces you to create the reaction in heavy oil, and not using what the lane gives you. Try standing around 18-20 and throwing up 8-9, playing it pretty straight. You'll find you'll get a more consistent, stronger reaction. You may need to play with where you stand on the approach, but you'll probably like the results once you iron out the kinks. To get our desired reaction, we need some dry and you have been avoiding it.
You current plan of attack requires extreme consistency in release and ball speed. (I tried it an failed) Now, if you really want to play in the oil, you can, but you will probably want an early rolling med/heavy ball, and you will need to be VERY consistent with ball speed. However, the lane condition dictates bouncing the ball off of the dry.
