Take a good look at each incremental time and compare run to run. 60 ft? if they aren't all within .005, there is work to do with the suspension. The mph should be stable and compare to the incrementals as well. If you are seeing a lot of variance only in the 60 to 330 or 60 to 660, might be inconsistancy on the shifts if your car is leaving wheels up and it is a little tough to shift exactly the same every pass. I narrowed my ETs by .02 with an airshifter. Also any slight directional change on the return to earth will throw my ET quite a bit, like .02 or so. I do carry the fronts out to the 60 ft, which I am sure is what aggravates the problem.