I wouldn't think a 24 row planter would "bog down" a gen 4 monitor. An old 2600 yes, maybe. 

Do you have all your measurements for the tractor/implement double checked? Your bar looks a little far behind the tractor icon but...maybe it's just the picture. As for your rates, if you put the Rx map in the background so you can see it....is there an Rx rate all the way to the field edges? What rate is it planting when it's "not following"?