That's practically 90% of your leg length, and I doubt you were previously pedaling tippy-toe. How did you interpret "inseam?" Because bike setup descriptions use that term all the time, when they're not referring to clothing at all.

In Greg LeMond's book, he also references the .883 x inseam measurement, but suggests determining your "inseam" by standing in stocking feet on a hard (i.e. non-carpet) floor, pulling an 1.5 inch book edgwise up snugly into your crotch, with one edge held against the wall. The floor to book-top measurement is the inseam he's referring to. I believe it generally works out to a saddle adjustment somewhat higher than the old leg-straight-with-ankle-on-pedal rule of thumb.