Probably boring to most people but I created a tool to nail exactly 40 hours a week contracting using the laziest possible inputs getting me out as early as possible on Friday:
Notice you don't have to give it AM/PM? Also don't have to give it any flags. It figures out what to calculate based on number of arguments alone. And it knows 9:45 to 1:23 is around 4 hours, not -8.
And during the week, decimal hours for timesheets: