First issue, you can’t compare the two original purchase prices unless you know when each owner put down their original deposit/reservation. 3xx3 Paseo Estribo may have been resereved many months before the other property, therefore locking in a lower phase purchase price.
First phase releases have typically been priced lower to generate interest and to reflect the added risk of buying into an undeveloped project. You must also have data relating to original builder upgrades that may have been added into the purchase price. Even though they are model matches with similar upgrades today, one unit may have been sold with inferior upgrades 6 years ago and subsequently upgraded by the owner. Although rare in this day and age, some upgrades may have been paid with cash or outside of escrow and would not be reflected in the final sales price. In this case, I don’t believe you should place much weight, if any, on the original sales price comparison.
Second issue, 3xx3 Paseo Estribo has an overall superior panoramic view from the rear. Sometimes AVM programs like zillow.com do not factor in view or location premiums correctly. Public records do not typically list these characteristics which is what is usually fed into these AVMs.
Based on a brief glimps at both properties in MLS, the 3xx3 Paseo Estribo property looks to be superior and all things being equal should command a higher sales price. This is a clear case of apples to oranges and I don’t think this example shows ample evidence of a trend in sales prices.
