Thank you, guys. I am beginning to understand. The answer to the question seems to be dependent on the time period. That does explain a few things.

When I said "roughly equal" to an Army Colonel, I was remembering a friend who retired as a Navy Commander. When I said something like that in casual conversation once, he was quick to point out that I had better not let a Navy Captain hear me saying that! Apparently a Captain who commands a ship takes exception to that kind of langauge.