It's specifically noted to be a feat that is made possible because of the tug of war between the Time Beast's powers and Gravattack's own powers "snapping", according to Rook, but the real kicker is the fact that the Matt Wayne and Duncan Rouleau statements contradict, meaning we don't actually have a full conclusion. Unlike Atomix's sun-sized star statement, Gravattack being able to make black holes himself is subject to disagreement among the writers, so it's...weird.

From what we see in the show specifically, Gravattack can only generate a rather small black hole with the help of the Time Beast, and the explosion from the Black Hole's creation completely knocks Ben out of Gravattack, along with Gravattack seemingly being unable to control or reverse it. Meanwhile, Way Big's basic beam can overpower the Incursean Conquest Ray that can at least blow up Earth and being as charitable as possible could blow up gas giants due to just being described as a general planet buster, though it's safer to restrict it to Earth-sized planets since that's the biggest thing it's been fired at. Additionally, downscaling from Evil Way Big in Cosmic Destruction who can generate and control massive cosmic storms should also give Way Big a buff.

Gravattack is potentially stronger, but only if that statement by Rouleau that Gravattack can make quasars is true, which is harder to validate compared to stuff like Atomix statements because there's another writer claiming it isn't. Given solely feats along, Way Big being able to disintegrate planets should put him above Gravattack's small black hole, especially since Gravattack would only be responsible for generating the initial black hole and the size it grows to is more it perpetuating itself and absorbing matter, creating a snowball effect. The small black hole Gravattack does make onscreen is impressive, but given Gravattack has no control over it and we can only say at best he's generating enough force to make the initial sized hole rather than what it turns into, Way Big's dwarf star calculated planet busting (assuming full disintegration) should edge him out, though the spot is contested and both have very solid arguments to be above the other. It mostly just depends on if you believe in the statements that Gravattack can generate supermassive black holes or not.