Mround and Ceiling are not round correctly as per system

Column D is the pro-rated holiday days produced by our system. I have tried to create the same on excel, but on some occasions, my formula does not agree with the system. I have tried both Ceiling and Mround functions but none of them are sealing the issue i have. In most cases, Ceiling has produced better result than Mround but not all the time.
I am thinking using Max function, but I hope someone could spot my error.