How often do you run into that tank that is solid from top to bottom? We get one occasionally and it really throws a monkey wrench in the day. Do you charge extra for the extra time involved?
As I was looking at the thread about prices I got to thinking that instead of a flat fee for pumping, we should break it down to labor and truck/gallonage charge. That way you could make up for those that take extra time.
You could bill it at x per hour for the man, x per gallon for the septage and x per hour for the truck while it's in use. Then if you had to clear a drain you would add on a machine charge as well.