Property Appraisal method / accuracy

[Brady Boyer]

I recently put a 4 unit property under contract and the appraisal came in 25K under the price I agreed to purchase for.  The seller was very set on getting his price during negotiations and I was willing to pay his price because even at his price its still a great deal. It will cash flow at ~ $1000 a month, so I want to get the deal done. However now the appraisal comes back below the sales price and I doubt he will budge on price. 

My questions relates to the accuracy of the appraisal. The appraiser used a comparable sales approach instead of an NOI method and I live in an area where there aren't that many 4 units to start out with. The most recent comp is 10 months old and the other two comps are older than 12 months and one of the three comps is 8 miles and 2 out of 3 comps are in different school districts than the subject property.

I asked the bank why an NOI appraisal wasn't done and they said they won't accept an NOI method as comparable sales is more conservative. They also have forced me into commercial lending since they say anything not owner occupied is commercial even if it were a single family home, so I find it interesting that they want to give me a commercial loan but won't use a commercial valuation method to value the property. Has anyone else heard of this or experienced this?