Some chinos have a machine stitched hem as you describe and some are done with more of a turn up hem and finished by hand or with a blind stitch machine. If they were previously hemmed as opposed to unfinished bottoms when you brought them to the tailor, they would most likely have hemmed them in the same way as the original hem. If unfinished, they decided how to finish the hem. Now you know to specify the method of hemming you prefer.
7/11/14 at 2:21pm