I understand what you are trying to prove here, in fact, from memory (I would have to go looking to actually find the relevant studies), you would be correct. If I am guessing correctly, your hypothesis is that younger people who make less money but have more time on their hands due to not having as many obligations (children, etc), care far more about balance than older people who have much more limited time to play. I won't indulge your fancy because I value my privacy to some extent, but I will say that for the purposes of your little experiment you should also require people to state the country they live in, because the US and the UK are not the only countries in the world and you need to adjust the income based on the cost of living depending on the country the person lives in. Someone living in Harare will have a lower cost of living than someone living in San Francisco.
Essentially, though I think that may also apply to people who perhaps have a disability making them incapable of work or have a low stress job - as those with much higher pay tend to have. But the issue is specifically with "game balance issues" that involve exploits like repeated saving - not game balance in general.
