I need to look through the thread, since I'm not sure what page Theorymon posted, but Round only goes up to 120 BP. Also the battle video post shows despite the break, Aurorus's Round does have 120 BP. Annoyingly, the PokemonShowdown Calculator doesn't have "Roud" as a Move.
252+ SpA Choice Specs Refrigerate Aurorus (No Move) vs. 0 HP / 0 SpD Regirock: 348-409 (115.6 - 135.8%) -- guaranteed OHKO
252+ SpA Choice Specs Refrigerate Aurorus (No Move) vs. 0 HP / 0 SpD Regirock: 174-205 (57.8 - 68.1%) -- guaranteed 2HKO after Leftovers recovery
I have another Video that shows 5 pokemon using Round, again broken by nothing.
Prygon -Z Round, Greninja Round, Gardevoir Round, Armaldo Rock Polish, Florges Round, Aurorus Round.
R24G - WWWW - WWW5 - S8LA
4 SpA Florges (No Move) vs. 4 HP / 0 SpD Porygon-Z: 61-72 (19.5 - 23%) -- possible 5HKO
4 SpA Florges (No Move) vs. 4 HP / 0 SpD Porygon-Z: 121-143 (38.7 - 45.8%) -- guaranteed 3HKO