This idea is ridiculous. First off the decay of absorb spells is without a doubt one of the dumbest things SE has ever came up with. Second with absorb spells we have the potential to turn a battle in our favor, except the absorbs don't exactly work correctly so this also doesn't work. Third if you wanted it to be useful you'd have to have be able to be used on multiple absorb spells so a 2.5-5min timer is way to long it needs to be at max 30 secs and then it would just be easier to remove the decay from all absorb spells rather than put this job ability in the game. Ultimately as its been said in many posts absorb spells need to be fixed in the following way: Remove decay, increase effect and duration, and allow it to be stackable with cruor buffs.