I'd take a passenger to really double check that you're on each scale individually. I don't know the post that you mention, but there is no need to unhitch or raise the camper off the truck (I thought I had read somewhere that it's against the "scale rules" to lower your landing gear- but I can't recall where I read that).
If I were you, I'd try to do 3 weighings:
1) truck and camper (truck front wheels on 1 scale; rear wheels on another and camper axles on the 3rd)
2) truck and camper (split the camper axles across 2 scales- make sure truck is not on the same scale as the front axle)
3) truck only (front wheels on one scale and rear wheels on another)
Weighing #2 isn't needed, but it may give some credence to the numbers in weighings 1 and 3. And saves you from lowering the landing gear on a scale.