Heal : 2000
WAR : 3250 + 2400 (20% Defiance) = 5650
PLD : 2600 + 2000 = 4600
1st Auto attack : 3250
WAR : 5650 - 3250 = 2400
PLD : 4600 - 2600 = 2000
Heal : 2000
WAR : 2400 + 2400 = 4800
PLD : 2000 + 2000 = 4000
2nd Auto attack : 3250
WAR : 4800 - 3250 = 1550
PLD : 4000 - 2600 = 1400
Heal : 2000
WAR : 1550 + 2400 = 3950
PLD : 1400 + 2000 = 3400
3rd Auto attack : 3250
WAR : 3850 - 3250 = 600
PLD : 3400 - 2600 = 800
So by the 3rd Auto-attack, PLD has more HP remaining than WAR. Not enough for surviving the next auto-attack, sure, but in the long run and in a real fight, PLD will stay at higher % remaining HP than WAR because Defiance only provides 20% boost to healing magic. And it's even before considering than one of those auto-attack might be blocked passively for an additionnal ~20% mitigation.
TL;DR WAR gets hit for 25% more damage than PLD but healed for only 20% more.
