I realize that this is late, per the date of your inquiry, but here's some helpful & current information.
As of April 1st, appraisers have many more hurdles to jump when doing their appraisals. In ost cases this includes a new Market Condition addendum; taking into account any "Seller Concessions" on active, pending & closed sales; factoring in short sales, pre-foreclosures, foreclosures, etc.; original list price & any revised prices...the list goes on & on.
For new purchases, the appraisals now have to factor in the pricing the entire time the home was listed unless it was off the market for more than 30 days (if I recall correctly). So if the price started at one point & dropped over time, the appraiser has to consider where it originally began & where it wound up selling.
Your appraiser (or rather, the appraiser that the bank hired) should be up-to-date on the most recent requirements. The "list to sell" ratio is something that the appraiser and the bank have to deal with, not you as the homeowner. Appraisers can call Realtors & ask for information on possible comparable sales, but the appraisers also have access to the MLS data, so I'm curious as to why the appraiser is stumped.
You'd also want to let your lender know that the appraiser appears to be having difficulty with the data requested in order to complete the appraisal. This may be a red flag to the lender that this appraiser is possibly missing some pertinent continuing education or is possibly not able to conduct the appraisal in a thorough manner for whatever reasons.
I hope you made it through the process & were able to refinance!
Restaino & Associates