Base health questions

So I’m watching some streamer playing through Raphael’s Final Act when I notice that, at lvl 11, all her characters have a base 160hp, with no buffs (except Karlach with the amulet of greater health on, sitting at 296). My lvl 12 playthroughs are lucky to have 2 members that even break 100. In comparing my constitution attributes to theirs, they are much the same. Tough feat can’t possibly make up that difference, right? Anyone know the cause for such a huge discrepancy?