yes I did exactly that. I felt angry but didn't express it in any way, these were tiny changes and lots of them, so I said it flatly, these will take time and w

yes I did exactly that. I felt angry but didn't express it in any way, these were tiny changes and lots of them, so I said it flatly, these will take time and will cost X hours. If he comes back saying "bet I could do this faster", I would tell them good luck. If he insists I do it for free, I would tell them it would force me to cut corners and would hurt me and the project in the long run.