Nokia Navigation :: Routing With Drive On Lumia 900?

So I finally tried to use Nokia Drive on a real trip (in New Jersey, USA) and I've noticed that the software often seems stuck on returning you to the originally plotted route when you deviate from it, instead of finding the best remaining route based on the new location. I'll give details for my particular trip in case this is a local issue.

We decided to take the NJ Turnpike to route 18 to River Road to Interstate 287 instead of 295 to 206 to 287 as Nokia Drive recommended (the routes are roughly equivalent in travel time, so I don't fault this initial route selection). When we entered the Turnpike, the new route kept trying to get us to 295 until we passed Exit 7 (In reality, past Exit 5 there isa considerable penalty to getting off the turnpike and onto I 295).

Finally, after Exit 7 it decided we should stay on the turnpike and get to 287 directly using Exit 10 (This too is roughly equivalent in travel time, so it was a reasonable suggestion). Once we took Exit 9 to route 18 instead it picked a different route than the one we are familiar with and this is where the biggest problem occurred. The route it suggested would enter 287 North at Exit 7, while the route we took entered 287 at Exit 9. It kept insisting we get back on its rout and get on at exit 7 to the point that when we were about to enter 287 at exit 9, it told us to get onto 287 *south* and take it to exit 7 where we would exit the highway and immediately re-enter it northbound. This is rediculous and should never have been suggested.

Am I right in my assessment that the software tries to stick to the original route instead of calculating a new one on the spot? What possible advantage can there be in doing it this way?