Here's what I think based on T&C's:
You can only enter 10 times per hour - BUT - there are 35 daily prizes that are drawn at 1100 the next morning, so you need to have the correct time period with the correct code, but I dont think it matters when you actually entered the information. The 10 times per hour is probably to stop someone using a machine to do it. Be aware you can only win one daily and one weekly prize per person (excluding SA). Also, according to the T&C's you should be entering a time frame, not the time (i.e. 1000-1100, or 0700-0800) AND they said it should go in 2400 format, so midnight being 0000, mid-day 1200, one pm 1300 etc.
Please feel free to correct me, otherwise, I hope this helps some people.