I got the e-mail and followed the instructions and got no change in my download rates as tested from various sites including dslreports. I called tech support and had them check my cable modem and there wee no problems, but it just hasn't happened for me. Maybe I can get it to change at some point, though trying the procedure several times didn't cause any of the settings visible in the hidden screens of the cable modem to change. At least everything works the same as before, rather than worse.
It is easier for a camel to put on a bikini than an old man to thread a needle.