Pretty sure the chat spam controls are done based on user, not channel. Try making a macro that does /say, /yell, /1, /2, /3 etc. all at the same time and I bet you only get maybe two off (pretty sure 2 simultaneous messages is one of the limits, there's several limits such as per second vs per minute or others).
As far as the addon version, that's actually network based (ie the number of packets your WoW client is sending). There's actually an
entire library devoted to ensuring you don't get kicked off for exceeding this requirement. Even with the library you will still get kicked off occasionally if you're in a big city or raid that sends an unusually high number of network packets (as there's no way in game to know exactly how much WoW is using baseline).