Between 2 Dates Problem

Okay I'm making a Test Book but it takes some time to remove data I don't need to add. While I'm at it the date that the forumla is run against has time in it. Perhaps the solution would be to add time in the formula. Such as Start: 0:00:00 and End 23:59:59? If that is the case then how would I add just that to what I have?

I believe perhaps the formula is automatically making the date times 0:00:00 so the End Date is not added due to this since it will stop adding at 0:00:00 that day.