Formula Help for Time Difference

[AvidanR]

I need help creating a formula that calculates time difference between two different dates and times. Sometimes the dates can be the same but the times can be different. In addition in a another column I need to calculate whether based on this formula the time difference is considered late or on time. This all based on the fact that any calculation of the time difference that is under 12 hrs is considered on time. I have a sample excel sheet that shows what I am trying to do with a formula for both but I dont believe that the formula for time difference is considering the less than 12 = on time rule.

PLEASE NEED ANY HELP BEEN STUCK ON THIS FOR A COUPLE WEEKS NOW!!!!!
Any help is super appreciated.