Today I racked up 61 floors... on a route with approximately five floors.

Sometimes I've seen wacky floor counts out by as much as ten floors (as compared to previous measurement of the routes, and my phone's own readings), but today my Instinct decided I'd walked 61 floors on a route that usually reads around five floors. I thought between GPS+Galileo, 3D movement, and the altimeter, surely there should never be such a massive error in reading floors? I guess not... :-(