And that is the main reason this spell is so complex. It does almost everything by itself and just needs magic and some will. This is good as a doctor can just cast the spell and not worry too much about blood loss for the next hour. But it also means that the magic cost is very high and like I said, it only lasts one hour, more if you overpower the spell but that's just a waste of magic with how much the cost increases compared to the time you gain.