Personally I find these new names somewhat confusing... When I see UUBL it seems to me that they should be usable in UU (at first glance, obviously makes sense after just the smallest amount of thought). I feel OUBL fits about as well (as BL is UU's banlist and pokemon that aren't OU by usage but still "OU") and is less confusing to newer players. Although both feel like suboptimal solutions and I've personally never had an issue with simply numbering them.