Mr. Wegner,
I would not "value" it, because that is the job of the market to determine what the value is or is not. My job is to determine what the market will determine. Beyond that, my job is to determine if there is a hazard clearly present. Or if I am unable to do that to call for inspections by parties that can. Prior to all of this, my job would be to contact my client in order to renegociate the SOW in order to determine with my client if this all will be approached with HC's, EA's, or not. If it will, exactly what are they? I will probably have to create them for the client and the client will have to agree to their use. IF my SOW was requiring 03/05 Fannie forms this would mean my client better expect either CB3 or CB4 coming at them. IF my client is wetting their pants wanting a CB1 report the ball would be in my court to determine if I can move forward or not due to my feelings regarding possible hazards without my being able to use any HC's or EA's to cover my tail feathers.
So my first step would be to redetermine the SOW. That would tell me to what extent I would have to determine functional obsolesence or not, and to what extent I would have to research additional market data concerning such situations.
Webbed.