Personally, I think that the CSV and website tables should contain the identical information so as not to cause confusion - i.e. you expect to download the identical table but actually get something different... In my opinion, errors in arcsec are significantly easier to use on the website (as you don't have to constantly multiply by 3600 in your head!). So I would say make both arcsec, but it's worth asking a few other end users to check their opinions...