Well, unless you have visible disproportion between limbs, it's ok not to lengthen your arms.
IMO, if your humerus and forearm look proportionate to each other and humerus descends normally relative to torso while the hands descend below crotch (at least to mid thigh), it's ok. The thing is your arms should look harmonious relative to your torso and pelvis. IMO, most people who have negative ape index at their natural height pre-LL tend to look bad even without LL.
Take Henry Cavill for example who, IMO, has at least -5 inch ape index. His arms look suspicious because he naturally has severe negative ape index, which is not the result of LL but he was born with it. The same goes for Artem Lobov guy. He looks weird because he was born with underdeveloped arms for his body.
Now, there are limits of course, no matter how harmonious your arm length looks relative to your upper body and pelvis. If you go for too much on femurs, the distance from hands to knees will look too long and it will look suspicious.
IMO, 2 inches on tibia and 3 inches on femur is the absolute max one can do if his arms look normal relative to his body pre-LL and if and only if he has very short legs relative to torso to begin with. If one is already leggy, he will look really bad with 5 inches of LL, there's no question about it.