Let me clarify a bit. I understand that the bus needs to sit to let the oil
drain into the sump. Even when the bus has been sitting all night, my
dipstick reads a higher level if I leave it in the engine for a few minutes.
Here's the scenario. I go out in the morning and check the oil before
starting the bus. It reads a quarter inch over the full mark. I wipe it off
with a rag and reinsert it into the engine. All the way into the engine.
Then I immediately pull it out. The oil level is now at the add mark. This
situation has caused me to consistently overfill the oil because I have been
trusting the reading I get when I wipe the dipstick clean and take a fresh
reading. Now I think the reading I get when the dipstick has been in the
engine for a while is the accurate one.

>>But if I leave it in for a few minutes it will read more than full. 
>
>That's because the oil that has been pumped up into the valve covers
>has finally drained down through the pushrod tubes and into the case.