Having hauled for a living I'm also a big believer in vehicle safety. My job and business depended on it.
I have a '98 chevy 3500 DRW crew cab 4x4 454 4.10 gears.
This truck weighs 3280 lb on the rear axle which leaves me with a 4220 lb payload in the bed.
I've been over dot scales scales in a eight state area along with feed mills/recyclers/CAT/stock yards/grain elevators/load dock scales/etc and never have seen scale readings other than in 20 lbs increments ie; 20-40-60-80-00 lb numbers.
Just curious but what type scales gave you numbers like 3175 lbs ??