Ultegra and Dura Ace HT2 BBs use smaller balls and there are more of them. Also, the higher level BB weighs a handful of grams less.

^ this is based on some bottom brackets I broke apart 4 or 5 years ago. They seem, the same for seal quality...just a cartridge bearing and a shield sitting over the bearing. Grease it all up and ride.
Spending $30 for a BB that is 'for racing' seems ineffective if the current one is smooth, but whatever I guess.