If you like the quality of work you received and the price is right, the rest don't matter. A routine wrap change shouldn't take more than an hour IMO. Having said that I have had some nightmare wrap changes where the last installer used the wrong type of glue and getting the old one off was near impossible. In those cases you end up eating your time because I try and stick with my quote. Building up or having to recut the wrap groove are both extra, over and above the standard wrap change and I charge accordingly.