GVW with wdh and without

I first want to say thank you for those who continue to show me patience and delt with my long questions and newness to this subject. I just want to be safe with my family. So I took the truck to the scales and this is what it read.

2003 yukon xl, 5.3, towing package, 3.73 gears.

1st pass with wdh
TV 6340, tt5380, gross 11720

2nd pass w/o wdh
tv 6540, tt 5200, gross 11720

3rd pass tv with full gas tank, me and 2 kids (50lbs)
tv 5760

First, does this look right. 780 tw, 13% of 5980lb trailer

Second, with the wdh I am 200 lbs lighter in the truck. Can I add 200 more pounds with the wdh hooked up or is this not safe? Do you guys always go by the tv weight plus tounge weight and not with what the wdh transfers.

Do you guys notice any major mph gains when reducing speed to 50/55 mph, I took it for a 1 1/2 hr test drive yesterday (on way to scales) and it looks like it was 8 mpg or so on the expressway at 60-65, it would down shift to 3rd (or maybe second) and hit 3500-3700 rpms or so to keep up 65 mph up a small hill. I think it is just the speed because when i was doing 50 up the same hill, it wasn't working nearly as hard.


Thanks Bill