That's the thing. They aren't high. They are the bare standard, normal. Every single full HDL paladin out there has 760+ defense. You worked really "hard" on those melds to catch up to the defense that Heavy Darklight gives naturally. That's it. And that's all you caught up to. We still get the HP and Enmity from it and are leaps and bounds ahead of your gearset in the application into viable endgame.
You aren't special. You aren't a high defense and VIT tank. High VIT is not needed, accuracy is more important and that's where you are making that tradeoff, not in armor but in accessories and weapon.
Can you please post a screenshot of your linkshell's DDs and White Mages? That's way more interesting than your defense and vit which everyone else has.