Some manufacturers don't seem to mind latency - on the Deere Seedstar if you stop in the middle of the field the only solution to avoiding a ten foot skip is to raise the planter, back up at least ten foot, put the planter down and go.

Another wonderful safety feature on the planter is there is no way (without bypassing something) to make the planter units run without forward motion - cant oil the chains or check things out without the planter moving - they will let you "pulse" it a tiny bit at a time. When I went from my home built Raven driven system to the Seedstar it is kind of five steps forward and six back.

John