By Cointracking.com you mean Cointracking.info right? I have used them for a while now but I never paid to upgrade from the free version because I didn't really like their UI. I also noticed some inaccuracies in my PNL calculations and it kept telling me I had more coins than I knew I did. Hopefully your tax guy looked over everything and caught any inaccuracies if you had them as well.

I would also advise that people periodically export their trade logs to CSV to have copies locally in case the exchange loses their data, or worse, shut down.