I think that's just the way some of us lose weight. My own journey is much the same, and I don't have commuting/long work shifts involved (I work from home). My weight loss goes something like this: Down 2 pounds, up 7 pounds, down 4 pounds, up 1 pound, down 4 pounds, up 3 pounds.... you get the idea. I have truly astonishing swings, and my weight loss graph looks like a bunch of icicles hanging off a stair rail. It bugs me, too, but I guess it's just how I lose... so long as the general trend is downward, I try not to get too irritated by it.
It's hard to accept, but I think you're doing beautifully overall! 67 pounds in less than 7 months? Wow!!