Appraisers are required to use the most recent sold comparables that are within the same building or area (if none are available in the building) for their appraisal regardless of when the contract was written. They take current listings and most recent solds that are most like the unit in question. Then they make additions and subtractions. A top floor unit is higher in value than a first floor unit. New construction sells for more than resale. The appraisal is there to protect the banks investment in the event of future foreclosure. If prices for the area increased since you contract 1 to 2 years ago then you will have no problems with the appraisal. If prices fell and your financing contingency period which should include an appraisal stipulation has expired and the property does not appraise then you would have to bring more money to the table.