I'm in the same boat, I have the big vest that you can't move unless it has wheels and i'm trying to get a smaller more portable one for college. We argued that it would increase my compliance since lugging home a machine that weighs more than I do whenever I go home would discourage me from bringing it home altogether and thus discourage me from doing my vest when I am home. I don't think it is unreasonable for you to try to get a better one. The only progress we got was that they would give us a credit for the vest I have now and make us pay $5000 (over a period of a few years) for a new one. We are appealing it for insurance, and if they don't change their minds we're just sacrificing the $5000, although this is hard while paying for college it's worth me staying compliant. So maybe try seeing if you could get a credit for the vest you have now?