It's quite possible it was angled forward a bit. Not all that sure. I usually focus all my energy on making sure the horizontal plane is level. Don't have the luxury of a tilt-shift lens or a film plane that I can manipulate.
Yes, I hit up the cave again. Took them on a tour to the back rooms where you really have to start crawling through some sketchy caved-in sections and then we turned around. Went about 3/4ths of the way to the "end." It was the first time I encountered moisture in the cave. Usually it's bone dry. Must have been from the recent rain. But it was so cool... There were actually drops dripping from the stalactites! It was awesome.