This is one of the idiosyncracies of Garmin. While Garmin makes very good GPSs, it tends to have this idiosyncratic tendency to add some features that some people do not want or to omit some features that some people wanted. Yes, you can say that this is the same of manufacturers but Garmin seemed a bit more pronounced. So, too bad that your 255W does not have a simple button that you can turn the autozoom off. This is the same for most, if not all the Nuvis, including the 3790t.
This is the one feature that puts me off the 3790t or else I would have bought one. But Big Bro thinks that it knows best what level of zoom drivers using Nuvis want, never mind that fact that thousands of drivers are individuals who have different preferences at different times. It is the most frustrating to find that, after turning a corner, the Nuvi will zoom all the way back until you can't see the road you are driving on.
choice bro.. yup support JCV but our maps cannot support it 