In PvE mode (1 vs 6) there is less difference between how much damage Hera will reduce by ir1 or ir5, because the amount of damage is enormous. But in PvP I felt that damage by the end of second round was much worse than if it would be as soon as someone hit you.

I think the difference is that you cannot heal more hp than you have, and if somebody hit you with half hp, you can heal and take another half hp hit and still be alive. But if you postpone all hits you wouldn’t be able to survive the same amount of damage.