just my opinion, I agree that I think your cumulative score gets you into Finals, but it's a wiped clean slate for the Finals run. I also think the number running in Finals needs to be reduced greatly.
My boy Kaiden was perfectly clean in all runs, and quite fast in UT Champs, until round 7 when he had 2 mistakes. He was 3rd going into that round. He fell to like 7th after that. I was devastated as we were never that close to a placement in Finals. Knowing we were not going to get a placement no matter how well we ran in Finals (I think we ended up 5th or 6th), I put it all on the line to push him as hard as I could since we had nothing to lose. And, that was fun!! Personally, I think Finals is much more exciting to have a slate wiped clean. You are rewarded for consistency to get to Finals, and if you reduce the number in Finals more than it is now, the few dogs running for final placements would be so exciting! It's kind of like when we have fun "time to beats" on rare occasion at trials, with Tunnelers, etc. It is much more exciting seeing everyone pushing for everything they have rather than just going out and running. That's the way it was when "Time to Beat" was first introduced in AKC. Everyone was cheering and screaming. Then, shortly after it became just another class. I'd like to see it changed, but that's just my feelings.