A 65mm drop would result in a high bb on a bike with 700cx32 or larger wheel, but not on a 650B bike. If you look through Bicycle Quarterly issues there is only one 650B custom with a 72mm drop, that is a Terraferma on a bike equipped with 650Bx42 Hetres. A lot of 650B bikes coming from custom builders have a bb drop of about 65mm, which puts the height at about 267mm, which is moderately low.