It’s the same idea. Instead of making a tighter spec and spending more resources making just the right number of parts meeting the specified tight tolerance, us

It’s the same idea. Instead of making a tighter spec and spending more resources making just the right number of parts meeting the specified tight tolerance, use a looser production tolerance and make a bunch of parts, and then (for an especially tricky use case) pick the parts satisfying a tighter tolerance after production, leaving the remaining parts for less demanding jobs.