Discount Problem - 2 for £X, 3 for £Y

[longshorts]

I am currently trying to set up a discount option for a product on my website, such that if a customer buys two of the item they get a discount, but if they buy three they get a slightly larger discount. (2 for £15, 3 for £20).

At the moment the 2 for £15 discount works, but the 3 for £20 discount fails to trigger when the customer adds 3 of the item to their shopping cart.

Any idea what might be causing this and how I can solve the problem? The trigger for each discount condition is simply a quantity, set to two different discounts one with a quantity of 2 and the other with a quantity of 3.

Thanks in advance.

[leehack]

Make sure the smallest discount is at the top, as it reads down the list looking for the first one that matches. Might be that.