I keep seeing you post stuff like this, but SSS is tuned to the the RDM. Usually its a bit harder than it should be, but its still doable. The DRG beating their dummy just means relatively, they should be better at DRG than you are at RDM, if it was a fair metric. Although, SSS is usually a bit too hard on the RDM and is overtuned. EIther way, its not a tool you can use to inter-measure between classes.
Earlier I saw you say that the tanks were out DPSing you, the only reason that should happen is if you die... and die allot.