I ran a search and couldn't find a good answer. Is this necessary to log? Won't it throw off the baseline amount of calories you burn for being sedentary?

I'm not sure of the answers to your questions, but just wanted to welcome you here. Maybe if I bring your post to the top, someone will be able to answer your questions much better than I.
So -

Hope you come back here & join in on the other threads around this board.

Several people on the forum have said that the result is more accurate if you log your sleep. I usually log sleep and any real exercise and then let the lifestyle setting take care of the rest. I do still think it gives me too many calories though.

Thank you