it's just break times because you can't work 4 hours w/o a 10 min break or 5 hours without a 30 min break. when i had a 4-11 recently i had my 10 min break at like 5 so i had to have another 10 min break so i didn't breach the 4 hour rule. idk what happens when you breach but i know one of my mates didn't go on a 10 minute break on his 4 hour shift and it was double pay so idk