I wouldn’t be surprised. Concerta (osmotic time release) is so much more effective than normal generics (non-osmotic time release) that they shouldn’t even be considered the same drug.
unmedicated << generic <<<<<<<<<<<<<<<<<<<<<<<<<<<<< name brand
in terms of perceived effect. They're sure as hell not close enough to be considered equivalent under any reasonable classification scheme (but I assume insurers really, really, really want the generic to count as equivalent and work to ensure it is so-regarded—and, anyway, availability's so spotty that we just have to take what we can get regardless).