said by clocks11:
... why doesn't anyone seem to get 4?
Actually, if you look through all of the modem signal screen captures posted in Johkal's »[Signals] Evidence of Upstream Channel Bonding - Post Here
stickied thread, while the the majority of the systems do just show having 2 or 3 upstream channels, there are a few systems that do have 4 upstream channels. See this previous thread: »4 Upstream Channels