If you find the device alters the route significantly, try:
A. Setting the preferences and map on your device to match those you set in BaseCamp. You’ll lose any waypoints the route contains but that maybe doesn’t matter, unless the route(s) contained some vital point(s) that you must go through.
B. Save the route you created in BaseCamp as a track. Then import the track to your device. Next, instruct your device to convert the track to a route.
C. Try inserting more shaping points, to better pin the route down.
But first, just try importing the route and see what happens. Does the route the device displays, match what you created in BaseCamp? It’s best practice to always do this anyway, irrespective. Why? Because it’s much easier to correct faults whist sitting comfortably at home, as opposed to at the side of the road.
PS See this thread and the excellent advice contained in post #5
I appreciate that this may be other sections but in case not....
I was getting frustrated by routes made on Basecamp not being replicated on my Nav VI despite having the same Navigation settings (Motorcycle Fastest Route -etc) and the same map versions on both Mac and Nav VI.
I then found that there is an option in the preferences in Basecamp for the route on basecamp to be replicated on the Nav VI. Screen shot below.