True, and also pre-existing asymmetry of the cheeks that may not be all that noticeable now, but may be when they are brought forward with the LFIII.
These things can be better anticipated with customized implants.
IMO, that's one of the reasons why LFIII (even the modified bilateral kind, where the two sides are moved independently) is not very popular. It's a general problem with osteotomies - witness how many people complain about asymmetry after jaw surgery. At least jaw surgery has the side benefit of providing a functional benefit (it's actually the main benefit, but people here tend to forget this). Also the soft tissue around the jaws is significantly thicker than around the eyes, so any asymmetry, step-offs are less noticeable (unless it's something like a severe cant). Asymmetry at the eye level is more obvious, because people look into each other's eyes in general.