As a thought experiment say you had 2 clones and each had LL surgery and the only difference in the entire process was the amount they lengthened wouldn't the one who did 6.5cm femurs have a better long term outcome compared to the 8cm one?
AS I stated before , 8 CM is the safe limit for most of surgeons . beyond that will cause problems (higher chances).
when I did my first assessment with my Doctor , he told me I am below average flexible , asked me how much i want to LL , I said 8 CM would be ideal , the max . he laughed and told me I might not be able to , but we will see how it goes .
with that burden , I decided to stretch my legs from day 1 of distraction . that led to my legs are straight POST distraction . it is HARD, but doable . ( so if you do the same thing but you can not get your leg to straight after a certain point , you can not do 8 CM )
and after 7 CM , I started to have muscle pain on my left inner thigh area , ONLY WHEN I LL , that led to me taking 7 days off in 3 weeks . the pain went away after I stop LL . and the muscles are growing back , my bones are healing well .
So lets get back to your question , it is proven that if you LL less , it will be less complications , But everyone is different .
I recently heard a case about a very fit guy who got to 5 CM on femur , but the IT band got too stretched out , he had to stop LL and take another surgery to fix it .
you should LL within your physical tolerance that your body will bear , beyond your own limit will definite cause damage to your muscle , nerve , joints , bones ETC .