I think you are asking the raven to do something it is not designed to do. Does it hold sprayer to the gpa set for rate 1 while traveling through the field?  Set rate 1 at 10 gpa, when traveling 7MPH it should put on 10 GPA. Slow down to 6MPH and it should still put on 10 GPA. When you want spray to stop when sprayer stops, you should turn off the switch on raven.

Here's a link to the raven 450 manual if you don't have one.

https://summersmfg.com/media/1550/scs400-series_scs-450-28-character-display.pdf