I need to offer an automatic 5% discount for orders over a defined value.

I then need to offer a 10% discount for orders with a specific coupon code entered.

My problem is that the 5% discount is applied first and that the coupon code is being applied not to the total of products for which the discount is applicable, but to this total less the 5% from the auto discount.

The effect is:

Order total: 500
Auto Discount: 25
Code Discount: 47.50
Payable: 427.5

What needs to happen is:

Order total: 500
Auto Discount: 25
Code Discount: 50
Payable: 425

I've tried various combinations of "Total of matching product(s)" and "All matching product(s)" but can't seem to be able to get this to work as needed.

Could anyone tell me whether this is a config error on my part or a limitation of the module, and, if this is the case, whether a fix or workaround might be possible?

Many Thanks,

Alan