I'm friends with several lecturers, and while they don't work 80 hours a week, it's fair to say they work substantially longer hours than I do. That's fine, they generally enjoy their jobs and get to do interesting things (as well as deal with a lot more bullshit than I do). You're utterly crazy if you think they spend only 10 hours a week on non-research activities.

As an outsider, your estimates are finger in the air at best. How can you possibly know you've covered all their activies?