Well the issue is it must be accomplished somehow in many instances. The fact that the sum of the various parts does not equal the whole is best summed by the analogy of the three legged stool - without one leg the stool has a significant diminished market value. The question becomes then is that third leg (personal property) more valuable in place (as part of a going concern) or separately?
You will not rent many rooms in an unfurnished motel. The FF&E is necessary to realize the market value of the property. But does the FF&E have a value of less than or equal to its contribution to the whole? Most likely independent of the bricks and sticks, the value of the FF&E is closer to its salvage or liquidation value, but in light of the highest and best use of a hotel, the value is substantially greater.
Such is the measure of highest and best use of a property as improved. the improvements may have a negligible value by their selves, but do the contribute positively to the overall value of the property?
No matter whether you use Linhoffs or Rushmore's methodology to segregate these values, the issue becomes conveying that relationship to the reader. I always begin by stating the segregation of the value of the independent components is a mechanical exercise required by practice and law. That the furnishings for instance, may have a greater contributory value to the property as a going-concern than they have independent of the property as a whole. In reality, the value of FF&E in terms of furniture, fixtures, and equipment may be equal to or close to its salvage value, but greater as part of the whole.
The bigger problem, as I see it, becomes attaching value to the intangible assets. The flag or franchise rights, or goodwill achieved by providing a desired service. To do this requires a deep reliance on economic theory, and not so much reality.
But then again some items of PP are relatively straightforward. A long-term care facility has little value without the Certificate of Need and proper licensing. And what is a building worth without the certificate of occupancy?