Hi Kathryn.
There are three reasons. Firstly, our software cannot distinguish buyers' previous purchasing history but can detect a purchase of three+ courses to enable the discount.
Secondly, this offer is no different from buying items in any retail store or supermarket eg buy 3 items and get a discount. However, you cannot say to the retailer that you want the discount because you have bought one item at a time over, say, the last 3 weeks. So our offer is no different than what is clearly accepted everywhere else in the business world.
Finally regarding your comment re not having funds to purchase in a group. Yes, we understand that and we did consider that for our customers, but considering that the purchase is via credit card, then the buyer has the option to pay off the credit card over a period to fit into their budget.
Steve (Health e-Learning)

Why is it not possible to be offered a discount when you have purchased 3 or more courses but paid for them one at a time. Some people may not be able to afford to buy 3 courses at a time. I have purchased 7 of your courses over the last 12 mths but have paid for them one at a time as I have not always had the funds to buy them in a group.