Not necessarily, at least not using software for throttling your p2p use. Its usually Cable companies that like to rip their customers off not 56k or dial up.
How ever non standard ports are still suggested and there will be days that will seem like everything is going great and others they dont.. thats not uncommon, also you have to remember the speeds greatly depend on who your getting files from, and their setups as well..
Keep an eye on it and we shall see how it goes..