I don't think there are any rules specifically stating that a DQ is required if not equal types in a box. Just 6 total pieces... that could be 5 slices and 1 burnt end or 4 wings and two thighs etc. Common sense to score best and courtesy dictate to include 6 or more of the same.
In my judging class it was stated that if multiple forms are submitted, the cook wants you to try both and then they should be judged equally. But if If a box has 6 burnt ends and 6 slices, I'm not even sure if a judge is required to select one of each. Couldn't they just select a burnt end only as their judging portion and grade on that only ?
Lonestar 24" Vertical offset w/ Insulated Firebox & Performer Platinum
Former owner: Jambo Backyard, Klose BYC, Med. Spicewine, Pitts & Spitts, XL & (2) Med. BGE's, 22" WSM & (2) 18" WSM's, 18" & 22" Weber Kettles