Do walkers not count as vehicles?

This is something I initially only noticed with the AT-RT, but it actually seems to apply to the AT-ST and Spider Walker, too. I noticed that destroying these vehicles don't seem to give you the amount of points you usually get destroying other vehicles, and most notably, they don't apply for the "Tank Buster" award. It's weird because even destroying speeders gets you "vehicle kill" points, but these kills don't.