...and I don't think King would want to be reliant on the tolerances of Mr Shimano for the inner interface with the crank spindle.
I would venture that anyone using King bearings would not be using anything lower than XT. IMHO Shimano's top end stuff is as well made as anything else in the alignment stakes. It would be a greater concern if the frame were not faced or a muppet assembles it.
Shimano are not perfect but in the whole rigmarole of installing components their quality control is hardly the weak link!
Also, would there not be a copyright issue with any firm makiing external BB bearings to fit Shimano this soon after the big S released it?
Somerset, like 'Heartbeat' with newer cars!
Retro MTB: 1992 Cannondale M1000 Deore XT M730. 1992 Raleigh Dyna Tech Quantum Deore XT.
Retro Road: 1992 Eddy Merckx Corsa Extra Telekom Shimano 6500 Ultegra. 1993 Dyna Tech Ti Campagnolo Athena 8 Ergopower.
Modern: 2004 Wilier scandium Ultegra 6800. 2014 Wilier GTR Dura Ace 9000.