So, if we wanted to run a promotion where a customer spends X, and they receive a discount of X, and the discount increases with the more they spend, would the discount app. that you mention handle that? Express does this all the time. If you spend $75, you get a $20 discount, spend $150 and get $55, so on and so forth. It doesn't appear that the regular discount feature in Shopify works properly. Correct? We will need an app like the Smarty app you mentioned?