I don't care personally...
I look at an ability like LoH and don't think Healing Surges... I just think it heals a quarter of max life, done, simple, easy and to the point. Enemies are monsters by the way D&D 4th works... so their abilities are not supposed to meet the same rhyme and reason that a PC's character does, SOOOO many cases of stuff in the MM where players go, "WHAT?!? That's not fair!! How come we don't get that??" Because you are not a monster and are meant to live for more than 30-60 minutes of gameplay! Monsters are cooler but meant to die!
So do I have a problem assigning abilities that "seem" like a player's abilities, and approximate their powers, but in reality do a fixed programming code? The undead knight Sir Cowen heals himself with a minor action for 24 pts, done! lol
EDIT: In fact... make it a recharge ability (5/6 or 6, or a recharges when first bloodied) so it only happens so often, after all, it is a mob ability, and is only meant to be used during that one encounter, not over the course of a day.