I guess not all nodes are affected equally. (While less than 28 this is the best my router can do). Do complain in the direct forums... Perhaps TS can put some pressure on rogers for them to upgrade your nodes.
Are you on a D2 modem or a D3? With the kids back in school, some nodes could be overloaded within the Rogers network. If it was TSI, every TSI user in London would see a slow down. I've said this before, but I wish TSI would stop selling D2 modems for any speeds above 12mb. Although technically it will work.. Rogers part of the network can't handle it without channel bonding of the D3 Modems during peak times.