Comp 1: $555,470 x .45 = 249,962
Comp 2: $501,680 x.25 = 125,420
Comp 3: $505,120 x .15 = 75,768
Comp 4: $452,320 x.15 = 67,848
You all are missing the forest for the trees.
The problem is is that he has not finished the sales comparison approach. There's a $103k range of adjusted values.....20%.... seriously!?! I mean come on. You cannot tell me that there is not some valuable amenity that has not properly considered, or that perhaps a non-market transfer is thrown in there; something is blowing up that range. Typical buyers just dont shotgun their purchases plus or minus 10%. You can't say 20% is just the normal background variation due to buyer caprice, and unadjustable intangibles?
The whole point of the SCA is that if you compare properties that compete in the same market and adjust, based on the market, for the differences between those properties, the adjusted values will converge at some number. In theory, if you had perfect knowledge of market reactions and had fully cross competitive and fully market sales you should be able to adjust to a single number. In reality, you really should be able to get to within 5% on all but the most complex properties. If the closest you can get is 20% you'd be better off just treating the whole SCA qualitatively as the quantitate approach is not particularly helpful.
In the case of the OPs numbers, I would have called the Listing Agent of the one that adjusted to $555k and said "I looks like you got a really great price for your clients on that sale. When I compare it with similar sales it looks like you got about $50k more than I would have expected. Was there something extra special about this property that caused the buyers to pay that much? Tell me what I'm missing here?" Then you shut up and let the agent talk. Seriously...9 times out of 10 when you do this the agent will reveal something about the transaction that was not in MLS and not evident from the street that will nicely explain the difference. When you're calling on the property that looks like it sold too cheep you want to call the Selling Agent...not the listing agent. "Hey, it looks like you got a really great price for your buyers......yadda yadda yadda." Listing agents like to bag about why they got top dollar. Selling agents like to brag about how they helped their clients negotiate the price down. Usually with the low adjusted price sales there was some defect identified late in the transaction, or some amount of undisclosed seller distress that drove the price down. With the high priced sales, you usually find out that was some undisclosed feature (view, upgrades) or concessions or personal property that earned the higher price. When you adjust based on this new information your adjusted values will tighten up.
As far as the OP's initial question. When you're sitting there with 4 comps that adjusted to within a few percent of one another, the reviewer doesn't care much at all how you reconciled because the dollar values become insignificant. With the 4 adjusted comps you presented, an error on your part could wipe out the buyers 10% down payment TIMES TWO, if your reconciliation logic was flawed. The reviewer was spot on to grill you about your reconciliation.