I've read in several places about a theory that loose skin can also mean we need to lose more fat. This is where going by the scale is misleading.

As discussed in this testimonial:

Lost the fat and the loose skin

I know there was a discussion on Mark's Daily Apple forum along the same lines...

It makes sense to me that the same metabolic "derangement" that put the fat on us can also need time to "heal" and our journey is not done until all the excess fat is lost. It seems counter-intutive, but what let us lose the weight might only be the first step: next comes getting the body properly rearranged at the right weight.

I have read extensively about people who have WLS, and I have yet to read an account of someone who got "all the way down." Because this procedure does nothing for their emotional state, and can actually worsen it, and because hunger signals return after a year, and because they often eat in an even more disordered way after such radical surgery; these people are happy and grateful with whatever they can lose. And so, while they "only" are fifty pounds away from goal or whatever, they cannot eat in a way that lets them lose down to where they need to be.

Imagine our own struggles in this area, and then imagine we can only eat a tiny amount, with all kinds of nausea and bathroom issues... and it is no wonder that, as I often say, I would do better if you gave me a year and let me put people in "low carb jail."