Fannie suggests the second parcel be valued in use , for its contributory value to the whole. They do not say the purpose of the appraisal is value in use. The appraisal remains a market value purpose assignment. I assume this is not an FHA assignment ( which specifies the second lot not contribute to value ). If it is a Fannie assignment, the second lot contributes X $ to the total value - which can be different than the $ amount the second lot is worth as a stand-alone lot.
I am not a fan of Fannie's statement on how to handle it, but it does make sense. IMO, they made this statement because some appraisers can not understand how to value an improvement sold as a package deal along with a second lot. When a the subject is sold along with a second lot, the second lot is encumbered by the same mortgage, and the owner would need to either pay down the value of the second lot in the mortgage if they wanted to sell it, or sell the lot and pay off the mortgage at closing.
Below from Working RE, their opinion of Fannie's newsletter on it:
On the Fannie Mae/Freddie Mac appraisal forms, the question “Is the highest and best use of the subject property as improved (or as proposed per plans and specifications) the present use?” is followed by “Yes” and “No” checkboxes. If the subject property clearly has excess land, as in the case of the house on two lots described above, the correct answer to this question is usually “No,” followed by an explanation that the highest and best use involves treating the improved and unimproved lots as separate entities in the valuation process. The fallout from this is that Fannie Mae will not purchase loans involving appraisal reports if the “No” box has been checked.
Apparently, Fannie Mae has been looking for a workaround to this situation. In their “
Appraiser Update” newsletter of December 2019, Fannie Mae advised appraisers that “Excess land is considered ‘value in use’ for the purpose of the appraisal, so the land should be described and it’s contributory value included in the grid.” That comment left numerous appraisers scratching their heads. The concept of “value in use” does not mesh with the definition of “market value” printed on the form, and thus did not resolve the issue of checking the “No” box regarding highest and best use.