I wouldn't call 30 minutes a late extract addition, just later. The dissolved sugars in wort will raise the boiling point of the water and decrease hop utilization, so I'd say you're correct in both of your observations. But since you want a debate
, I'd think that if your later extract technique results in better beer, that you're compensating for some other fault in your technique or recipes and should instead by trying to find the cause.
Aside from that, I believe there are many ways to make good beer.