All I can say is the one I have does. It recalculates the route.
I did pay big bucks for it when I bought it. I just wonder if these new ones that are so inexpensive lack the capability the older ones have.
I do think that all these constant update requirements syncing to your computer is just another way for them to gather information and nothing more. 9 years and counting with my GPS and I never have hooked it up to my computer.
Curious, On the ones that are 'installed' in the cars do you have to take them out and update them with maps with your computer??