i don't understand... why would underpredicting or over predicting matter?
150/100= 1.5
50/100= .5
distance from 1 in both = .5 =50%
right?
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That is method 1 yes... but there is a different way of looking at it... which comes about because for people who under-predict, it is unlikely they will ever get more than 50 points from a prediction.... you have to predict as low as half of what the real figure ends up as to get 50 points.... over-predicting it is quite easy to get 50 points by being a little overconfident. Last year there were a number of predictions that were more than double what the real figure turnd out to be, so they gained over 100 points.... a feat which is actually impossible when under predicting unless you predict negative numbers.
With method 2... it is possible to get 100 points when both over and under-predicting.... if you predict either half of the real, or double it, then you would get 100 points.
That's all I was asking, because neither of the two methods is totally fair by itself, Method 1 is definately more correct though because it is comparing directly to the real sales, instead of to the predictions (see above post for the maths bit)
I should have thought you would be all for me trying to make it fairer when you have such high predictions on all 5 consoles. 
I am fine with leaving it as it is though, it's a perfectly ok way to work it out and I don't need to do extra work.
