So far, the scale rot has not returned (thankfully! it got really bad there for awhile).
I'm wondering if it's not still a humidity issue causing the failure-to-shed. We don't really have an accurate way of gauging the humidity level at the store.
There's another snake housed with her (I know... don't get me started... I have no control over that) and he has no problems shedding.
I'm kind of limited to what we have in-store for resources... the best I can do is one of those stick-on dial humidity gauges. I guess it'll be better than nothing. (The thermometer is a digital one with a probe)