1) I think some items could be sorted in the wrong coefficient. Maybe

should be coeff.4 (instead of 3), maybe

should be coeff. 3 (instead of 4)...
2) It's possible that there are differences in the coefficients... Your Soda seems to be a slightly rarer coeff.3, just like the Candy Cane is a slightly rarer coeff.4 item. Also, the robots seem to appear quite frequently to me... though they are definetly not coeff.2. This could also be a reason why *1)* is happening as it is...