Oh yeah, we also run super singles on all drives and trailers... This lightens the whole setup by about 1600 pounds (400 pounds per axle with supers)
Tag weight is generally with zero fluids or driver n drivers effects. Put it on a scale bobtail full of fuel n that will give you a true number. As a power only you'd be good to know that # anyway- the couple times I've done power only that was a contributing factor to the higher rate.
I load 53500 or a regular basis, using the tractor pictured, single, single, double , single, then double back. kind of really need to know your light weight, At IWX, and LaCasey I loaded 46 to 47,000 all the time, load nose light so you can adjust it with your tandems.
Don't mess with your steers if there between 11500 and 12500 leave them alone, it will just add to your aggravation.
I have a 16 Crapcadia, and with a 53' dry van Utility trailer and about 3/4 tank of fuel (twin 150s) i can scale 46,000. BUT, I DON'T LIKE IT... and i discourage it. Anybody that wants to max you out to the limit should be paying TOP DOLLAR. Usually those loads are the ones that pay crap. I know yours is a contract load, so hopefully that's squared away