Elevation Band Volumes do not match Cut/Fill volumes

[Anonymous]

So I've done an earthwork analysis for my site and CAD tells me I have 9.1 cy of cut and 129.8 cy of fill with a net fill of 120.7 cy (noted in the Earthwork Analysis table in the attached image). I've also added elevation bands to my surface and created a table to show amount of cut/fill in in 1/10-foot intervals (noted in the EX vs PR Wearing Surface table in the attached image). My question is why don't the volumes in the second table add up to the net volume of 120.7? The cut/fill factors are 1, and the intervals with negative values were counted as cuts.