I have opened a route (ie, CR Beavermouth to Ottertail) and immediately saved it as a new route (CR Beavermouth to Ottertail - XX) and session (CR Beavermouth to Ottertail - Default XX) so that I can modify this new "base" route and default session. After making some changes/modifications, I go to the Save As option and sometimes it gives me the option to Overwrite the existing route and existing session, but a lot of the time it only gives me the option to overwrite the existing session. Is there a particular reason for this inconsistency?