I found their skills quite unnerving. I have a great story told to me by my thesis advisor regarding a (high-powered, Ivy med school) Md-PhD student who called him RANTING in the middle of the night about the lab's screwed up balances, and treatment group rodents who were apparently defective since they couldn't manage to survive even modest dosing on a per kg basis. Yes, "five kilogram rats" and "20 mgs per kg" was apparently lethal. My thesis advisor (then the lab's head post-doc) apparently hung up on him at that point. Which was probably kinder than laughing.
Ahem. 
Man, I love that story. Math. It matters. More to the point, I've told that story to a LOT of future health professionals that thought that my grading re: unit conversions in freshman chem was "harsh."
As for grading scales, just so you know, MOST colleges now want them "unweighted." So you'll only have to calculate them on that basis anyway. Yeah, for the purposes of class rank and all that, there are a variety of schemes. Deliberate choice of words, really. LOL.