I too think count-back system is silly. It works OK in a statistical system, where opponents are repeatedly paired against progressively stronger opponents (like the Swiss-system), but I don't see how this is in any way relevant or meaningfully applicable to HFT.
Never mind the World's competition, I don't think it's fair even in a standard UKAHFT round. Those people shooting in the morning session can get quite different conditions to those shooting in the afternoon. Like what happened at Fort recently.
I think those people in a tie-break situation, should shoot another 5 targets, modified slightly on the main course. It's no more effort than what we have now. Then if there are still unresolved positions, it should be sorted out by unsupported standing sudden death. Incidentally, there are a small number of us, who have dodgy knees and take kneelers standing -not fair!