To me, when a company gives the leeway to a character stating that they have the power of a million exploding stars, I believe that they've given that character near infinite power, and at any time can give him the power to save a crew of people dangling from a skyscraper to saving a planet sized vessel or greater from total annihilation.
It's as if Marvel broke the mold with this character, and the only way to keep him under wraps is to say that his power level depends on his state of mind, and then slap an agoraphobia sticker on the back of his head. Now once that was all said and done, they'd send him out as an apparent mid to high class 100, while knowing that he is actually quite a bit more than your average muscle jockey, which allows for the same amount of leeway that DC uses for Superman to be equally used for the Sentry by Marvel.
Superman was holding back, Sentry's mind wasn't stable. blah, blah, blah.