What you say is true Paul, but with Garmin making "lifetime" updates pretty affordable, I have gone to that. When a map update becomes available it updates both my computer and my GPS so they are always in sync. I have never had an issue with my GPS (Zumo 450) reprogramming a route built on my computer as a result.
Good to know. I'm still using a 276C and Nuvi 265W.
Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell http://www.bigbend.net/users/glaves