1. The amount, if any, which when added to the acquisition cost of the dwelling acquired, equals the reasonable cost of a comparable replacement dwelling which is decent, safe, and sanitary and adequate to accommodate such displaced person, reasonably accessible to public services and place of employment and available on the private market. The reasonable cost of a comparable replacement dwelling shall be determined by analysis of existing available standard dwellings which are functionally equivalent and substantially similar to the acquired dwelling and located in a comparable, but not less desirable, neighborhood, in accordance with a method approved by the bureau of relocation, unless otherwise provided by federal law.