Nighf surfer not stable /Data ****!!!

So I've noticed that if i start using the night data from 00:01 it doesn't work. Rather it starts from either 00:16 or 00:30 depending on what i dont know... I usually use my night data for downloading huge videos and stuff... Sooo today which is not the 1st encounter, night data did not come to party instead it chowed my once off bundle and the funny thing is that i started surfing the net from 00:38... I try by all means to time it but still Telkom ****s me!!!!