Yeah well this is a reason why I don't think they should've gotten rid of the GAF.
In situations like this it clearly explains something very succinctly. Also from personal experience if you took the GAF seriously the numbers were accurate. What happened most of the time IMHO was that clinicians weren't referencing the chart when making the number and allowing the insurance directive to mandate the number. E.g. "do we want to keep her inpatient longer? If so make GAF 15 even if it's really a 45.
As you hint at, the GAF was used in a way that rendered the numbers meaningless. Either someone fudged the numbers for insurance reasons, or providers really had no idea what the anchor points were and just threw in a number that sounded fine to them. I don't know how many people I saw with GAF scores of about 40 in treatment for what I would say were mild to moderate anxiety/depression, working full-time/going to school etc. In theory, it sounded useful. In actual practice, just another meaningless piece of information in the chart.