I review appraisals all the time. It amazes me how often the predominant age is exactly the age of the subject and the predominant value is always the value of the subject property. It doesn't matter if it is the smallest home in the subdivision or the largest, it is the predominant value. Does anybody read Fannie Mae guidelines? The forms were developed by Fannie Mae. In 16+ years, I rarely find any neighborhood where I can say the predominant value or age is one number. Heck, it takes 3-10 years for some subdivisions to be completed. Do a truthful honest job and just give a predominant range of value and age if that is the truth. If underwriters don't like it, ask them to read the Fannie Mae guidelines.