Does anyone else think that the heart-crushing deaths are inconsistent?

Daniel died almost instantly after having his herz ripped out. However, I will state that it was probably because Cora crushed the herz almost immediately. After Milah's herz was torn out, she felt to the ground and was clearly dying even before Rumple crushed the heart. Old Henry died immediately after the removal of his herz even though it was still in one piece! Graham on the other hand managed to live for twenty-eight plus years without his heart...and he probably would have lived for much longer if Regina hadn't crushed it.

Has anyone else noticed this inconsistency between those Du have died from having their hearts ripped out/crushed?