New Print Layer start/end location?

I have a flashforge creator pro with sailfish replicatorg. I'll print something and for each shell layer, it will start and stop at the same location. The end result is that I get a noticeable and unattractive line on the part. It doesn't even seem to be totally consistent. 1/2" of building along the z axis later it could change within that print. What causes this? Is it in the code somewhere or just my printer's behavior. And is it something I can change (can I move this starting point of each layer off to another side)?

Start and stop point of each layer is controlled by the slicer. Most slicers have a setting to make it random if you choose to.

not repg or makerware (as far as I know).
simplify3d does.

It's particularly noticeable in cylinders.