"...only in drinking and raising hell..."

In April 1924, F. Scott Fitzgerald resumed work on The Great Gatsby. In a remarkably self-lacerating letter to his editor Maxwell Perkins, Fitzgerald chided himself for neglecting his art in pursuit of his legendary brand of dissipation (all italics are original):

A few words more, relative to our conversation this afternoon. While I have every hope of finishing my novel in June, you know how these things often come out, and even if it takes me ten times that long I cannot let it go out unless it has the very best I'm capable of in it, or even, as I feel sometimes, something better than I'm capable of. Much of what I wrote last summer was good but it was so interrupted that it was ragged and, in approaching it from a new angle, I've had to discard a lot of it--in one case, 18,000 words (part of which will appear in the Mercury as a short story). It is only in the last four months that I've realized how much I've, well, deteriorated in the three years since I finished The Beautiful and the Damned. The last four months of course I've worked but in the two years--over two years--before that, I produced exactly one play, half a dozen short stories and three or four articles--an average of about one hundred words per day. If I'd spent this time reading or traveling or doing something--even staying healthy--it'd be different, but I spent it uselessly, neither in study nor in contemplation but only in drinking and raising hell generally. If I'd written The B. and D. at the rate of one hundred words per day, it would have taken me 4 years, so you can imagine the moral effect the whole chasm had on me.

That phrase "something better than I'm capable of" strikes me as odd, with the implication that he wouldn't submit his new manuscript unless it was of a quality beyond that which he was capable of creating. In other words, an impossible condition, unless Fitzgerald happened to be blessed with some sort of genius "writer gremlins" who spiffed up his work while he was otherwise distracted, perhaps by drink or hell-raising.