First, I agree with I-Wire as to the actual loading. When we de-rate, we do so based upon the size of the circuit breaker. This is just fine when you are applying this method to dedicated equipment- but, to assume that typical household convenience circuits are ALL completely loaded ALWAYS is simply silly. Yet, the code makes no distinction between a 20 amp circuit for a 19 amp refrigerator... and a 20 amp circuit that's feeding maybe 5 amps worth of TV and stereo!
I also think that there is a proposal for 08 that more closely defines "bundling," I've had a few disagreements over at the HI forums, where many seem to favor a definition a lot more inclusive than mine.
