In my Greyhawk, Jensen radio/gps, the manual has a disclaimer saying that the unit's guidance may not always take your vehicle size, length and weight into consideration in route planning.
I, too, have a Garmin RV760 and love it.
2016 Greyhawk 29 MV
West Branch, MI
Wife & Co-Pilot: Famous Amos
1 Shizu, 1 Havanese