First, one of the things you have to remember is that the computer software is also used on units that are not capable of recalculating a route.
Next, it is a lot easier to enter stuff on the computer than to use the tedious entry on the GPS. While a route that only goes from A to B is not a big issue, entering a route with multiple waypoints is done much more easily on the computer than the GPS. So even if it did recalculate the route, there is still a case for computer entry of the waypoints.
Ask before recalculating? Sounds OK to me. I acutally find that the GPS sometimes calculates a different route than the computer anyway. Sometimes that is good and sometimes it is bad. In the long run, it may have been easier to program the GPS to act the same all the time than to make an exception for downloaded routing. They may even be omitting some of the download data to conserve internal memory since the unit will calculate the route anyway. Of course some of the last few things are only conjecture.
Well. that was sort of my point. Why route on your computer and then just have your 60cs overide all of the routes with its own re-calcs? That doesn't make sense since the 60cs can route by waypoints just as easily as on a PC. The reason most people route of the PC to download is because they wanted a SPECIFIC route to take and it's much easier to play around with the different roads to get to a destination on a PC than on the 60cs.
That's why they should take a different default when someone chooses a pre-programmed route from the 60cs. It should just follow the route as it is programmed WITHOUT re-calc, or at the very least ASK if you want a recalc. Put another way, the auto re-route should be turned OFF by default when using a pre-programmed route from the route list.