I get it. We did the same when our first was in care - my husband works shift so when he woke up on his day off it was usually around noon. Half of the time he'd take nap time to mow the lawn, get groceries, run errands, etc. and pick him up at 3.

Having that said, we weren't drop off at open, pick up at close type of people anyway, and we never argued or complained about payment when we needed to get him early, when she was closed and what not. If I had a family off for 3 weeks and brought their kid every day or their kid was the first or last there like the others mentioned, it would get annoying.