I finally was able to log onto my Schwab account and download successfully without having to change my username. Apparently, this is required if one previously provided their log on information to TT; otherwise, no need to change your current username.
It seems that it took the weekend for Schwab and TT to recognize each other. At least now I can save some time and not have to enter transactions manually - although I still will double-check to confirm accuracy.
I hope others have similar success!
