Maybe total damage mod used to be 100+% and description wasn’t changed since then? Pretty much the only hint is this topic from 8 years ago, lol.
And what do you mean by “feels very weak”? Did you play it? Because in you link there’s no actual build, just a skeleton of a build, if you will. In general Pox can’t deal any significant damage on its own. It’s a decent trash killing skill, and OA reduction is nice, so it has its uses regardless of rather weak damage.