Stupid and trivial question about bimax

[abeilletoimême]

On several occasions I saw people with recessed lower jaws but, at first glace (to my greycel eyes), normal maxillas asking for advice, and everyeone was telling them to undergo a bimax. The issue is, isn't bimax a surgery that affects both jaws? So what's the point of suggestion bimax to someone who has a recessed lower jaw, but a normal maxilla? Wouldn't a surgery that would reposition solely the lower jaw more appropriate?

I'm sure this question is gigaretarded and has a very trivial answer, so I didn't want to pollute Looksmaxxing section and posted it here instead