Agreed. You only adjust for a difference between the subject and a comparable. If concessions are typical and common, and the subject has similar concessions, then what are you adjusting? For ecample, if the subject has an inground pool and a comp has an inground pool, would you adjust for an inground pool? Not if you know what you are doing. Same for financing concessions.
No. Concessions are the only thing not adjusted against the subject. You do not adjust them like a pool or other amenity:
Fannie Guidelines:
"Comparable sales must be adjusted to the subject property--except
for sales and financing concessions, which are adjusted to the market
at the time of sale."
You are looking for the cash equivalency of the comparable sale. The adjustment is made whether it is common or not. The standard is based on whether the seller is paying costs that are a matter of tradition or law the buyer's costs, and it has nothing to do with typical or common. If the seller is paying $4,000 in closing and the comp is paying $4,000 in closing costs, and the payment is cash, than the cash equivalency on the effect of money to the seller is $4,000 and it gets adjusted.
A very extreme example, but a real life example is a report I did near Disney there in a condo market where a builder began offering a $40,000 selling bonus to any outside sales agent who brought in a buyer. These units stopped selling for $180,000, no sales in 6 months, and once the builder began offering the $40,000 to the agent, they started once again and sold at $180,000 to $200,000. Other projects, reducing their price, still were not selling because the agents weren't showing them. So other builders and the resale market began offering the same bonus. This leveled out the playing field. Now, I have an appraisal to complete on a refinance in the project and all my comps, inside and out, have sold for $180,000 with a $40,000 bonus. Is the house worth $180,000? We know it is not because the builder was unable to sell them at $180,000 for a 6 month period and since that time the market, in general, has declined. What type of an adjustment should I make?
I found an old sale that closed prior to the concessions being offered, read the market for % of decline based on MLS data for the period, used the old sale, adjusted for market time and the unit adjusted to $150,000. I made a $30,000 adjustment for concessions across the grid showing that one sale as comp #4 and two listings that were both adjusted for the anticipated concession being offered. My client was livid because the other appraisers appraising those units were coming in at $180,000
"all day long" he said,
"and since all current market sales now sell with the concessions as well as the subject, there should be no adjustment" (this is your argument too). I said,
"I'll tell you what, the sales office was closed for the week I did my report and they couldn't help me, but I'll call them and see if they have anything else, perhaps that sold without the concession and is recent. Maybe values really did go up." I'm sure I sounded incredulous. Turns out they had two sales that actually closed 2 and 3 days after my effective date and neither had a buyer's agents involved. Their price? $150,000 and $153,000. Asked why it wasn't the whole $40,000, they explained to me that they'll negotiate but never give back the whole thing because in their experience the buyer's agent and the buyer usually have a little deal on the side with the $40,000 bonus.
I have another example, much more involved that includes a guaranteed rental income by a builder for more than 2X the amount of market rent over a period of 4 years, guaranteed as well. But the result is the same. The adjustment is made for the cash equivalancy effect on value (direct cash = direct cash) whether all the comps are selling with it or not. If the seller is doing something he is not required to by tradition or law, it is a concession no matter how typical it is in the current market.
I'm not sure what you said, I just saw my name in one of your posts. But I'm certain you're wrong. 
