BOPO – Is there a way that the user can add more boxes?

Hi, thank you for the plugin it is helping me a lot. But i have noticed that similar plugins on Shopify have the ability that you can add more boxes as a user. We would benefit from this if this would be a option for BOPO to.

Let me explain it a bit more:
The user selects their products, but the standard bundle offers 3 options. But he additionally want to add 2 more without the box discount. Like now it would not be clear why they need to pay, so it would be nice if there was a way to add more boxes in a seperate section. But these kind of upsells would be super useful.

I know there are shopify plugins who are capable of doing this. I have added a image of one.