Did you "set up" your tractor, first?

Meaning, enter tractor model, then GPS receiver height from the ground, and GPS receiver distance "in-front-of" the centerline of the rear axle, and then distance from rear axle to drawbar hitch pin, and distance from rear axle to lower 3 pt hitch pins.

Note: Once a tractor gets "set up" , then it makes sense, that a person has to add the distance from WHATEVER hitch mechanism(drawbar or 3 pt) that was used to attached the corn planter with and the Ag Leader system needs to know that extra distance to where the seed drops to the ground.

Example: JD4440

 120 inch to GPS receiver (for height)

28 inch in front of rear axle centerline to GPS receiver

24 inch to drawbar hole from rear axle centerline

34 inch to lower 3 point hitch pins from rear axle centerline

Example : 8 row JD7200 planter (pull-type)

13 ft 8 inch from drawbar hole to bottom of seed tube

[Note: I'm doing some of these numbers/measurements, from memory, but you should "get the idea"]

If you do a good and accurate job, with your measurements, then Ag Leader's suggestion for their row shutoffs(timing) will be very close to perfect. (it was for my application) When you build a configuration with a certain tractor and a certain planter.

 Configurations for me, I named mine [JD4440 JD7200 8R 6 sec] for corn; (= 8 rows and using 6 sections for row shutoffs)

 I also have a [JD4440 JD7200 15R 6 sec] for soybeans