Yeah, that is probably what will happen. I just don't feel like getting on the phone and trying to explain to them that I troubleshooted the hell out of my setup, and it's their modem. Oh well, life.
I use Bell ExpressVu for TV, so the splitter deal isn't an issue. At least, it would have been a while ago.
Testing it somewhere else is not really an option for me unfortunately.
Thanks for all the help nonetheless.
Will keep posted.