30c to 8c because of noisy hospital and poor protocol, page-37

Actually you did a great job to describe the method of LOOCV.

LOOCV from what I have read is the best possible method for learning algorithms! But because it's so expensive to calculate answers due to computations required - it's not used as often as it should be. There are two ways to obtain calculations of LOOCV, one is quick and easy and less accurate "short cut" method. The other one which if your correct in pointing out, is what the Prof is doing which is much more complex and time consuming but obviously more accurate.