Seems reasonable to me but it depends on what they provided. If it's a small project it may not be reasonable. You can deal with BC yourself - they are quite reasonable people, well most of them I have dealt with have been. Make sure you get a few quotes to compare and check they are professionally qualified too. 🙂
I would defo skim it. I did mine and am only a novice diyer, but with practice, and a good trowel I did a reasonable job. If you are doing it yourself make sure you joint tape the boards together and allow 10 days to dry then mist coat it. Good luck!