when combining several effects on a single character, ie:
– Shield mastery +1d1 AC level 0
– Shimering scales +1d2 AC, SR level 0
Additive effect of these for AC should be 1 + 1d2, however it is calcuated as (1+1)d(1+2)=2d3 which is of course much greater. Not sure if this is within rules since it allows some very powerfull skill combinations. This happens whenever buff rolls are stacked together.