And just a note to add to what Merrix wrote: it seems to be common that longer cylinders can be implanted if a re-do is necessary some time down the road, ie. several years, even if the original implant was sized correctly. AND, the second surgery seems to be easier to recover from than the original, possibly because all the spaces for the components do no have to be "re-carved" as it were.
There is some hope in the future if you find yourself still dissatisfied. Believe it or not though, there are a few advantages to being on the smaller end of the scale. You just discovered one!
