I have received your message, and I want to make sure we respond. All RVs are built by hand and there could be a couple of reasons for the difference in weight.
1. improper / mistaken weight label. This does happen when water (some or all) is left in the tanks at time of weighing. This is an accident when it happens. This sometimes happens when a vehicle is winterized (yours was winterized when it left the plant). This COULD have happened, but it seems likely. This can also happen when a person or two is still in the unit when it is being weighed. This is also a mistake, but we do our best to insure this does not happen.
2. options - the dry weights listed on web/brochure can be very different depending on the options listed. For example, on your coach, you have the 2nd A/C, 4 door refer (very heavy), high gloss sidewalls (heavier than standard walls), and solid surface countertops (not included in standard weight).
The 3596RE Big Country is a large coach, one of the largest Heartland builds. Please keep in mind that Heartland's trailers are not the heaviest, nor the lightest in the market. Heartland's 5th wheels are truly the "goldilocks effect" - just right for the size. If trailers are too light, they may (in most cases) lack the critical components that promote long term life. On the flip side, if a trailer is too heavy, it may not be using the newest and most up to date construction methods. Heartland takes special effort to insure well built trailers with the latest construction methods.
In the past, if we have ever questioned weights, we have used CAT scales. Curious, what truck are you pulling with?