Big,
My best guess is that your guitar may have a short dovetail join, which would mean that the bottom part of the heel (where you see the cracked finish) is glued to the sides of the guitar.
At some point, whether by simple string pressure on the neck (150-200 lbs of pull, all the time), or an 'event' (your 'drunk roadie' dropped the cased guitar), the neck has been stressed to the point that the dovetail part of the neck moved and the 'lower, flat heel' part didn't move. So, you either have a crack in the finish, or a crack in the heel and the finish.
I'd take it to a luthier and have 'em look at it.....