I worked at a company that considered 35 hours 'full time'. Maybe you just assumed something? 36 hours, 40 hours, while I know every penny counts, it doesn't seem THAT significant to me, once you take out taxes, etc. Why not just pick up 5 hours somewhere else on your four days off? Maybe another place could fit you in, and while you wouldn't be able to work every single time, you could most days. Just a thought.