KParser doesn't retain the order that items drop. Items are stored in the database in the order they're encountered and not revised beyond that. So even if it dropped in your theoretical order, Byrth, if you got a mythril ore the first kill, then a diorite and mythril ore the second kill, the order in the database would be 1. mythril ore, 2. diorite.

As for the groupings, those are only sorted by number of drops, and then I think the items list is alphabetized.