Wait - you mean when we put in a Rate limit in the PCQ ?
I remember back in the day when the dual QoS first came out I just put the PCQ as the queue in the first step solving this problem and shifting it to a problem of not specific user limit 
. 
Sorry I had forgotten about this
Thanks for bringing the attention to this problem though. It is interesting indeed.
Before the two-step with PCQ there was the massive Queue Tree