Hmm, it occurred to me that where I heard this may not have been the "official" solution. (I'm never sure what the official solution is.) Someone comes up with a solution that's relatively correct and the various details might be different. But that solution is the only one I've ever seen.
So I tried to Google this specific puzzle and I'm not seeing this added detail as part of the answer anywhere. Only that this is his only source of income and he's afraid he won't be a midget anymore.
The extra detail does add an extra personal issue to it if you still want to try to guess it.