When looking at the graphs in the QOS, the one things I wish it showed was a total amount of ACTUAL bandwidth currently in use.
Currently it shows everything broken down by rules and it always adds up to 100%. That is great as you know that the totals all add up, but what is the percentage of the bandwidth that it is USING as a function of the max upload/download limits as defined by the QOS system.
Thing of it this way: Everything might add up to 100%, but you are only using 34% of the total allowable upload bandwidth, and 55% of the download bandwidth.
The reason I think it might be heplful is when you are getting lag or other issues and are you at a bandwidth limit or a QOS classification limit? It is more of a quick snapshot of how much bandwidth is currently being utilized.