Yes they are. It is calculated the same way as a post these days. I found out the hard way and realised soon enough that it is wise to wait the 15 minute period before upvotting a comment.
Not everyone has realised this and have done a post the other day highlighting our bad habits and ignorance towards this. If you vote immediately after receiving a comment you have basically just thrown your vote away handing a majority of the curation to Steemit.