I think I'll stick with my plan then. There are boards that end not on a joist all over the place. The fact that the tongue and groove held them together this long is proof that it does work--to some extent. That board happens to be in the middle of room, but it was originally close to a wall in what was 2 rooms. I may be nice and repair some of the others too. My landlord has been very nice and has told me repeatedly he hates to see me go.