The sale of a new property will have the "EP" included. So subtract out the cost of the land and you have the cost of the building. If EP exists then that figure will be higher than the cost to construct with the remainder being EI/EP.... have fun...
I think this is risky because it isy backing into the cost approach and assuming the new home sales price is legit and is market value...is the sales price inflated due to builder financing, cash back, is the buyer legit buyer or investor, are the new home sales prices in the community supported by resale listings in the community and competing outside new and resale homes that are similar?
You have to do the cost approach as the cost approach, what it costs to build in area, including contractor profit and cost of land best as can by land extraction. The problem with the CA is there is no separate line for "market appreciation", or ent profit/incentive...is it supposed to be in the CA? And if it is can you simply add in endless amounts of EI/EP to match the sales price? What if EI/EP is based on sales prices that are not supported by the market?
This is the risk when appraisers start adding in market forces with cost figures and true locational ext obs in the cost approach...they either start backing into the CA to include enough EP to make the number work or backing out of it by adding enough OP to make the numbers work...the market forces are already accounted for throughout the appraisal in either rising or falling prices, supply/demand, comp homes sale prices, listings etc....is extracing appreciation/depreciation per market and then sticking it in CA appropriate, if the EP is irrational exuberance or based on flipping etc? And what if the EO is based on flopping and investors profiting off low values? Is the CA supposed to be a "brake" against the acceleration of the appraisal toward market forces, re a reality check for users of the appraisal, or just another market value indicator neatly lining up with the SCA?
When markets are in balance, when builder profits are healthy but not based on huge cash back, builder financing only, selling to straw buyers to set the first sale prices etc...then the contractor profit in MS is actually enough or close to what the homes are selling for. When resale prices go crazxy high, real legit builder profits rise but actually lag behind resale prices, unless the new home prices are unsustainable, which is what happened at market high 2005-2007.
When resale prices fall below economic indicators and are a crash due to prior too rapid acceleration, the builders cannot make any profit and abandon building in the area and go bankrupt etc...here and there a spec home but most new construciton is halted.