As I understand it, a Norm is suppose to be the average of all the samples in a given group. If you got a selection of 1, 1, 1, 2, 2, 3, 3, 3 your norm will be 2 (1+1+1+2+2+3+3+3/8.) The idea of a norm is to measure the average of a group, not define a 'goal' for all the samples to be adjusted to.