I think a better phrasing of his argument would be "if you take that job, the additional costs will not outweigh the income you get from that job". Put in anoth

I think a better phrasing of his argument would be "if you take that job, the additional costs will not outweigh the income you get from that job". Put in another way, your net surplus after a month will be more with the job than without, irrespective of whether it is actually positive.