The stacks might have reverted back to that state since they've been like that for so long they are probably broken in to naturally resting in that position.
When I say taper, I don't mean hem the length off, but rather to make the leg opening smaller. It shouldn't take much... perhaps just bringing the leg opening in by ~.5" should help them settle a little bit better. You also could hem off an inch or two, though, if you would rather go that route.
If you can go to a store and try on 17.5cm, I would suggest that. They're a lot skinnier than 19cm in pretty much every area. You appear to have pretty slim legs, though, so 17.5cm might work for you.