30 years before DGSD, Xiao Yuanshan single-handedly wiped out an assembled team of elite martial artists; only a few lucky members survived, including Shaolin Abbot Xuanci, former Beggar's Union Chief Wang Jiantong, the nameless Zhao Qiansun, and Reverend Zhiguang. These survivors were able to live either because they had fainted (Zhao and Zhiguang), or Xiao Yuanshan intentionally spared them (Wang and Xuanci). But Abbot Xuanci knew that eventually they would have all been wiped out if the battle continued. Now, 30 years later, Xiao Yuanshan is roughly the equal of 3 Xuanci's. Also given that Xuanci was supposed to be the best in the pre-30 years team, it's probably reasonable to assume that 30 years ago, Xiao was also just 3 times better than Xuanci. And yet, Xiao took on much more than 3 Xuanci's and won, because it was a duel to the death and he went all-out. Reasonably, I would think that Xiao Yuanshan accomplished the equivalent of "= 3 but wiped out 4".
Now, let's look at the LOCH situation. IF Wang Chongyang were the equal of 3 Greats at first Huashan Tournament (which would seem to be the case if he = post-ROCH Greats), do you think he could wipe out all 4 of them if they decided to gang up on him in a duel to the death?