There's half-crimped and there's half-crimped... I naturally hang the BM edges with pinky and index quite open, other 2 fingers are kinds half crimped, same on a campus rung, many would call that half-crimped, but then there's full on chizel half crimping where you force the index to half crimp and it's very active, like CWP advises in his fingerboard vid. If you're talking about the former, then I would suggest that you are a freak Ian if you can hang f3 drag longer than on 4 (i.e. your preferred grip on those edges is pure f3), and that csl is quite normal in hanging much longer on 4 than on 3...
