If AOG was exactly on the line at the two points that you compared, then that 4" offset when you return on the same pass means your offset is wrong by 2", which is what your other measurements also indicate. Also your f9p should have a circular plate underneath them for ground plane.
I have these plates. I would need to make my extrusion wider to be on the outside of the roof mount bolts. I’m worried about tree limbs as these plates are not metal but copper clad FR4. I’m basing my center on the roof mount studs. I would assume the cab would be in the centerline of the tractor.
Why is the offset 6” one way and 9” the other way with the planter? Planter tracks fine and I just put new parallel arms on it today.
It hurts my brain to think about this, but I think you might have a combination of a wrong antenna offset and a narrow implement that is masking the problem.
Set your implement width to 30’. Drive an AB line, then turn around and drive the same AB like back in the other direction. It should drive back in the same wheel tracks if it’s setup the way you expect.
So an 120" implement.
If everything else is set correct, it could be a slight roll difference. or the WAS is just a little off center. At least I know those two does affect side offset. So if you know Roll is 0 deg. (or same + or - with tractor parked at same almost level spot, but front of tractor in opposite direction. Then you can adjust WAS until you have the correct spacing between your rows.
ALSO with Disk wheels on the planter, you can be absolutely sure it is capable of dragging just the amount of inches we have here!
I had similar problem but it was all fine after I deleted all vehicles and made new ones from one I knew was okay… i spent hours on the field measuring tractors center, implement width, tool ofset, antenna offset… I found nothing.
Try it and see if it helps… for me it worked, I cant see any difference between 6th and 7th corn row and we planted with 6 rows… its perfect.
Don’t think it will do any difference. Does your tractor really also drive same inches wrong, when going same ab line?
BOTH directions with implement lufted!