WOW unlike Coles doesn't print the expiry date of fuel discount...

WOW unlike Coles doesn't print the expiry date of fuel discount offers on the bottom of its loyalty card holders shoppers receipts.

Thus if you are a WOW loyalty card holder before filling up you have to go online to see if you have a current discount or simply take your chances when you go to pay.

Apparently this may be why some shoppers with loyalty cards prefer to shop at Coles to get a receipt showing details of the petrol discount which they can either put in their wallet or keep in their car glovebox. Some shoppers apparently also drive to a further away Coles Shell garage to have the certainty of a current discount.

Might this partly explain WOW's falling petrol and supermarket sales.

If there is nothing in this point why is Coles system different and why does WOW print the details of other offers (eg liquor offers) including date of expiry on the receipts of loyalty card holders.