Splitting hairs 101

We're short-handed right now (because obviously, with the economy in the shape it's in, how can they possibly be expected to find anyone looking for work?) so I'm working two 8 hour shifts within one 24 hour period. The first one is winding down now and I was told a manager would come in to relieve me "between 6AM and 7AM". I have a feeling that I'm going to be reminded, in word and deed, that 6:59AM is between 6AM and 7AM.