Two maps covering the same area, CNEUNTU 2017.1 and Autodrive 4.50
A simple route with just a Start and a Finish clicked on the map.
The same Basecamp profile, Off Roading and Route Preferences set to Shorter Distance and in Road Type Avoidances only Unpaved Road left unchecked.
Nuvi 3490 set to Faster Time and in Avoidances, only Unpaved Roads checked (3490's SW tends to use the bigger-faster roads this way).
First thing to notice is that Autodrive applies the Off Roading profile much better than CN, that has the same unpaved roads but uses mostly paved roads (whatever I've changed in the profile, I couldn't make the CN to create an Off Road route like Autodrive).
CN and the red route
that uses mostly paved roads, although there are many dirt roads that are "shorter distance" (as the profile is set).
Autodrive and the blue route
that is correct, according to the Off Roading profile.
3490 with Autodrive map and blue route (created in Basecamp using Autodrive map)
Notice that the time for the uploaded route is different than in Basecamp, because in Basecamp I've changed the average speeds of the roads, something I can't do in 3490, which calculates the time (not the route) according to its SW and the map speed limits.
3490 starts the routing immediately after I press GO. The route is exactly the same as in Basecamp, although the 3490's SW is set to avoid all Dirt Roads and to calculate the Faster Time.
3490 with CNEUNTU 2017.1 and the red route (created in Basecamp using CNEUNTU 2017.1 map)
Again the time for the uploaded route is different than in Basecamp and also different from Autodrive's, because each map has different speed limits for its roads.
3490 with Autodrive map and red route (created in Basecamp using CNEUNTU 2017.1 map)
Even using a different map than the one the route was created with, 3490 does not re-calculate the uploaded route because there are roads from where the route is passing. Maybe it would re-calculate using its SW if some roads were missing in this map.
3490 with Autodrive map and CHANGED blue route
When I go to the trip manager and change something in the uploaded route, like the order of the points and press SAVE, 3490 now recalculates the whole route from the beginning, according to its own SW rules and avoidances.
Even if I change back the order of the route points, as they were in the uploaded route, again the re-calculation is done by 3490 rules and I loose forever the original uploaded route
Now 3490's route uses only paved roads.