Board Thread:Questions and Answers/@comment-176.92.186.100-20130223085138/@comment-62.31.154.71-20130223141025

Yes they can. If you put a stack of the item (e.g. stone x64, ender pearl x16)  you are sorting into the sorting machine GUI, then it will sort those items in stacks. However, if there isnt a FULL stack of the item, then the sorting machine WILL NOT recognise that the items are the same and send it to wherever unsorted items go within your system