I've bowled on the Chettah Pattern 3 times now and it's been 2 different ways. Twice they have played with a lot of  oil on the oust side and really dry in  the middle. I was playing straight up 5 board, if I hit 4 It was a washout, if I hit 6 it was brooklyn. I tried to move outside to 3 board. I hit the 3-6. Then I figure, what the hell, I move way inside play around 15. Ball come in like a truck as long as I don't get it out to the oil.

The other time I played the Cheetah pattern it was the complete opposite. Dry as the desert on the outside and back end and a flood in the middle.

EACHTIME the lanes were oiled just before bowling on them, they were at the same house, same lane machine, same laneman. The only difference is that when there was a lot of oil on the outside it was in the morning and when they were drier it was at night. I don't know if this makes a difference or not. I'm asking because I'm bowling a Regional PBA and this is the shot that will be put down. I am so lost on how to play this pattern. I thought that it was supposed to more of an outside shot, but twice that I've played it it was an inside shot.

Any advise would be helpfull, thanks

If there is oil on the outside and dry in the middle its not the Cheetah. Thats more of a reverse block. The second description you gave sounds more like the Cheetah. 

  http://www.bowl.com/Downloads/pdf/SportBowling/pbaExperiencePatterns/USBCPBAExp_Cheetah.pdf  Check that out.