The NADA values are a percentage of the MSRP, based on a fixed depreciation schedule. So you can figure out NADA values for your rig from new until the year ought. But since theyaren't calculated from the selling vaues at auction, like used cars, the NADA value can differ substantially from reality.
For example, optional items don't usually figure into selling prices, unless its a really popular option....in other words options on a used motorhome are usually free. Rare options may cost you something, but if everybody selling has whatever it is, only a few sellers will set their price to allow for the option.
OTOH, issues like the closing of a manufacturer can affect the buying price, but won't affect NADA, so it opens up a difference in pricing. Fashion changes will do the same thing so unpopular colors or floor plans can revise the price downwards without affecting NADA values.
Currently planning for retirement.....planning to build a small home in Nova Scotia for summers and someday year-round. Trying to sort out a good way to spend winters in central Florida as I can't drive anymore.