mobile application – Target iOS app’s quantity selection workflow

I use the Target app on my iPhone device to buy “household goods” related products in order to use the drive-up drop-off system they have. When adding a product, the Target iOS app hides the quantity dropdown from the user until after the user has added the item to their cart. It then opens a modal allowing you to select either pickup or drive up, then prompts you to add the item to your cart again.

The app then prompts you for < 1sec to update the quantity. If you click it in time, the app bugs out and tries to return you to the modal, which appears to break it also. The easiest way to update quantity in my opinion is by going to checkout, clicking on the product again, clicking the add to cart button again, and clicking the quantity dropdown from the modal.

I think as a user of the app that this UX would be pretty good from the perspective of the mobile experience, if it worked. I assume from their (Target’s) perspective that in most cases people are buying only single items so deemphasizing the quantity dropdown is a good trade off in order to have more open space in the app.

Is this type of “add product” mobile UX flow actually preferred over always displaying the quantity dropdown ?
If so, would this still be preferred in the mobile web experience?

Im thinking of trying it out either way but I’m interested what other people think.