I used discount to set up three discounts: one for 10% off an order that is over $50, one for 15% off an order that is over $150, and one for 20% off an order that is over $500.

I have not been able to get the rule to work if I add both conditions, i.e. the order is greater than or equal to $50 but less than $150. So what I did is create the three rules like this:

10% off an order greater than or equal to $50
5% off an order greater than or equal to $150
5% off an order greater than or equal to $500

So this way 5% is added as you go up, which equals to the 15% and 20% discounts. But I am running into an issue.

I have a shopping cart with $60 worth of products. However, the first two rules are both evaluating to true. The amount is only $60, so it should not evaluate to true since it is not >= 150. The >= 500 rule is working and evaluating false.

I'm at a loss as to why it would evaluate true when it obviously is not true.