^^^^ Exactly.
It's pretty hard to screw up machining the body portion of a typical FL expander-ball die. Can't say it doesn't happen, but the biggest screw-ups in FL dies I have seen occurred in the 1980s, when RCBS decided to save money by first reaming the bodies of cartridges based on the same basic case (such as .243, .308 and .358 Winchester), then afterward reaming the neck portion of the die.
Had a few of those where the neck did not line up with the body, but didn't realize it. Could NOT get the rifles to shoot consistently--until I replaced the RCBS dies with some made the old-fashioned way, by reaming the entire FL die with one reamer. Finally figured it out after acquiring my first concentricity gauge around 1980--and being informed by a well-known accuracy gunsmith what happened with the 1980s RCBS dies.
The big advantage of Lee collet dies is that they don't require case-necks to be very consistent in thickness to produce accurate ammo. They do best (as all dies do) with consistent brass, but if you don't want to sort/turn necks they're a great solution.
