Checkout Basket - Change Quantity popover

One of the things that annoy me most about checkouts on iPhone apps is how much space is given to the 'change quantity' buttons.

They are usually huge and often don't get used that much because 1) you can do it on the product page and 2) how many times do you add a pair of jeans to your basket?

I came up with this little popover to change the quantity, the amount is underlined to show it can be tapped. What do you think?