The truth is that most Kangs are 2 slightly off axis backflips and a late 180. Everyone grabs japan which drops the shoulder.
Whether the "math" adds up or not, a "kangaroo flip" (god, I hate that fucking name) is traditionally a dub rodeo 9. I can think of a handful of people who are doing dub flat spin 9s (B-Paul is the best example...Wallisch does one in the new Jiberish edit), but, if you watch Wester, Jon, Andreas, etc. there's no way you could call those tricks dub flatspins.
On a barely related note, I'm tired of this whole "flat 3" phenomenon. Just because someone does a backflip with a japan, everyone's calling it a flat 3. Give me a break. I can think of a few people who do true flat 3s, but the majority are fraaaauuuudulent.