Just an FYI, the 5k Sherline is the same scale as the other two with a different dial. So, if anyone has a lighter model and wants a 5k, just order the new dial. This is what I did and it's as easy as threading one out and the other in. One other thing to remember is to never pick up the scale by the weight pad. It will pop out and you will have to bleed the scale to get it back to accurate.
As to the accuracy of manufacturers weights, I'm certain that varies widely among manufacturers. Mine was under 100# difference than what XLR said it was. Likely from batteries and propane. And, when I loaded it for travel, it only went up another 150#. Loading the garage with 2k lowered it by just under 300#. Not the norm but like I said, all RV's are different so what anyone else has found, unless they have your exact make and model, means absolutely zero about your potential buy.