Yes itroll does work independently of tiller , but only throttling up,
ie..if itroll is at 22% you can only throttle up at tiller not down.
I give this unit 5 stars, it has such a sensitive and minute control over throttle compared to tiller control.
I also have a spare servo and have not needed to replace in 5yrs? now.
It will control up to 2 motors if needed (main and kicker)
Easy to install with simple tools.
Again, great addition to the boat