https://www.zillow.com/homedetails/110-Confederation-Way-Irvine-CA-92602/25520651_zpid/
This was listed first in 2018 at $980 and finally got sold Feb this year at $808k. You can do the math how much % that is and it's much higher than your 10%. West Irvine is pretty close to NP also.
980k for this is way overpriced especially backing the tollroad, so realistically this would have never sold at 980k. I've seen 4/3's in West Irvine going at this price point or less. I actually saw this home on redfin when it was first listed but is a hard pass when backing the tollroad. Homes near major roadways should always be less than comparable homes farther away in my opinion.
https://www.redfin.com/CA/Irvine/29-Keepsake-92618/home/40102842
The buyer would have paid $52k more if bought in Oct. 2018 when first listed. Good thing they waited.
Are these comparable homes that sold in 2018 to your above example?
https://www.redfin.com/CA/Irvine/82-Cienega-92618/home/12253701800k, but ~200 sf bigger price per sf is cheaper here
https://www.redfin.com/CA/Irvine/39-Bell-Chime-92618/home/21928642,762k, but ~200 sf smaller price per sf is more expensive
Both these homes are <5% sold price diff from your example.
List price vs sold price isn't an indication IMO since you have some crazy sellers out there. I could list something at 2mm when it's actually only worth 1mm on the market, does that mean someone saved 50% when they bought at 1mm? Do you have examples of similar detached homes where the diff in sold prices are 10% or greater?