Normally an Insane for a song like this would be AR 9, however the Extra would use something like 9.2... just for the sake of it? As object density in both diffs is quite similar in most points, having the harder one lower AR while using more simple structures makes for a more unique experience. I think that would be lost if i made Extra AR9 too.
I didn't tell bns this on fire because spread is the main point of this set and not having it judged by setting it on fire is kinda counterproductive, I wanted 3 bns because there could be more things wrong with this than a regular set