Man Hours for Tongue and Groove Siding

I recently started a job installing tongue and groove cedar siding in a 12x24 Jacuzzi house with 10’ high walls and an 8/12 cathedral ceiling. I downloaded a trial version of “National Estimator” to figure the bid. It gives 0.035 per square foot for 10’ lengths. That’s 100 SF in 3 ½ hours. Does that sound right?

This is the first time I've done a job like this, but still…
After cutting everything to length, cutting out for the electrical, re-cutting some but joints for a nice tight fit, and then making sure everything is level and lines up around the room, it seems like it should take longer than that.

I realize that the man hours will be different above 9’ and also on the cathedral ceiling. However, even below 9’ on the walls, is 0.035 HRS/SF a reasonable number for 1 person who’s working alone?

Bob