Any question answered...

It's all about cost. There's usually a version with metal cups foe an extra couple of quid. In the aftermarket, you'd be an idiot to try to save a couple of quid, but to OEM buyers every cent matters.

Ah I see. In that case, any idea where I can get a 110mm BSA BB that'll work with Stronglight 2000 cranks and doesn't have plastic cups?