My mother is having her alterations done by the same seamstress that I am working with for my wedding dress. However, I have my wedding dress alterations through a package, since I bought my dress through the shop. The seamstress agreed to do my mom's alterations for her dress (not purchased through the shop), on the side, as a freelance job, so the cost is based on the rate the seamstress requested. In this case, should she tip? She was unsure and asked me, and I don't really know either. I would lean towards yes, a set amount rather than a percentage, if she is pleased with the work. What do you guys think?