We’re counting the skills they’ve already finished as where they’re at. Also we’re not counting if it’s just one crewman, since you can dump a ton of personal manuals into one guy. If your commander has 7 skills, but the rest of the crew has four, that would count as only four.
Let’s have a good discussion as to what tank the crew’s in as well. I’ve heard every kind under the sun, from the french lights to russian heavies. It’s also easier than ever to get good crew thanks to books.