Here's a description, I saved from an Ag Leader Blog:

by Andrew Pierce on June, 18 2015 in DirectCommand™

Now that planting season is winding down, spraying season is starting to pick up. Here are several tips for troubleshooting your system as you begin spraying this summer.

What if my boom sections are turning on/off too early or too late?

The first step is to verify the application offset is measured and entered into the display accurately. The second step is to adjust the look-ahead settings. The look-ahead values are how far the system looks ahead to turn sections on or off. The values should only be changed by 0.1s at one time.

Boom sections turning ON too late

-Increase Turn-On Look-Ahead

Boom sections turning ON too early

-Decrease Turn-On Look-Ahead

Boom sections turning OFF too early

-Decrease Turn-Off Look-Ahead

Boom sections turning OFF too late

I-ncrease Turn-Off Look-Ahead