Interesting experience. I have had similar issues, and when added together with other offers (eg: get 5x your shop when you buy minimum $xx on meat/fresh fruit etc etc) I cannot for the life of me reconcile the points total I earn back to what I should have earnt from the shop based on my calculations. I just put it down to the system being deficient and unable to process stacked offers properly, and it is probably also a part of what you have discovered - that T&C's seems to contradict each others - so then it's anyones guess as to what is actually programmed into the system and algorithms to calculate points earn.