Here is how I might, (writing for bb purposes ) summarize the HBU analysis and assignment condition:
" The subject of assignment for an opinion of market value is 32 Cherry Street, a 2000 sf dwelling on a 10,000 sf lot, together with adjacent lot address of 34 Cherry ST which is a lot of 10,000 sf. The total lot size of the two lots will be 20,000 sf. The vacant lot at 34 Cherry Street is excess land and can be sold sparely. It might have a different value if sold separately with a HBU as a buildable lot. However, the lot has been vacant for many years and the demand for vacant lots for builder apparently not strong enough to have produced a buyer for this lot. The HBU of the excess lot when encumbered under one mortgage with the subject dwelling Cherry Street is for assignment condition purpose is analyzed as a contributory value in use. Its value in use is to provide additional privacy and green area, with potential for expanding house or building amenities on it such as a pool or shed, or alternatively can be retained as a future investment. "
"The estimate of value for the lot of 32 Cherry Street is a range of $75,000 -$80,00 as a vacant site The value of 32 Cherry Street in the appraisal is estimated for its contributory value to the whole at $60,000 as long as it is conveyed together with subject dwelling. "