Yes, you can hire a qualified professional ahead of time to do a BPO or an appraisal. HOWEVER, an appraisal is an opinion of value. These values can differ from person to person, bank from bank depending on experience and education. Not all of these professionals follow the same guidelines. I am an appraiser and also a real estate agent. Under the appraisal license I can do both appraisals for federal transactions and BPO's and also as a real estate agent I can do BPO's. The BPO's I do are very different from that of a real estate agent. I deal with many different requirements from many banks and not all of them require comps with 6 months, as just an example of one requirment commented on. The bank will be using a 3rd party company that has a list of people qualified to do the BPO. All of them are not created equal. Many investors who purchase short sales hire their own professional and submit a BPO with their offer. Good luck!