Two common reasons this happens in my experience: 1. He's dissatisfied with the rate he agreed to. He's inexperienced and so instead of renegotiating he's just

Two common reasons this happens in my experience: 1. He's dissatisfied with the rate he agreed to. He's inexperienced and so instead of renegotiating he's just inflating to make it worth his time. If you pushed him down on price he may feel stuck. If you refuse to increase his rate or allow for padding he'll probably walk at some point pretty soon. No one likes to feel taken advantage of. 2. He might do more work that you're unaware of, like prototyping and research, on his own initiative. It's easier to attribute that time to something you asked him to do rather than something he decided needed to be done. P.S. Why would it be hard to pay him? International wire transfers are absolutely trivial.