Steamroller? What Steamroller?

I help organize our local store's monthly Warmachine tournament and we have had a bunch of new players show up on league night lately so I figured it's time for a Mangled Metal event. Normally I'm a bit of a fanboy for official tournament rules like Steamroller, so even when I'm not happy with the current state of that rules set, I try to follow it anyways as if gives everyone a common ground of understanding, everyone uses the same rules. But as I looked though the Steamroller Doc for the Mangled Metal rules, I just realized how many events I've been too or even helped run that are not supported by Steamroller. Also I realized Mangled Metal is not listed in the steamroller rules. Both the Genesis and Resurgence where not steamrollers and I'm always seeing people use Mangled Metal or "progressive army size" as a tournament format, but that's not supported as a Steamroller format. It never occurred to me, to not run a Steamroller if I was able too. So the next event I'm helping run will be Mangled Metal.