You could write negative hours. E.g. if 0 is at the current 10am, a workday will start at -2. There'd be two ways to name the same hour, but it wouldn't be con

You could write negative hours. E.g. if 0 is at the current 10am, a workday will start at -2. There'd be two ways to name the same hour, but it wouldn't be confusing.