Tag based Discount button on Settle Screen

Hi everyone,

I was sure what I’m trying to do would be straightforward, but I seem to be hitting a wall and can’t see where I’m going wrong. I’d really appreciate some help.

Desired outcome
I need a button on the Settlement screen that allows staff to toggle a 25% discount on and off (in case it’s pressed accidentally). The discount should apply only to food items.

What I’ve done so far
I created a Product Tag and tagged all food items as “food”.
I then followed a tutorial for auto-updating prices based on tags. This one:

In my setup, I only used one tag, one rule, and one discount.

Finally, I added an Automation Command button to the Settlement screen and changed the Rule Event from the tutorial so that it is triggered by pressing the Automation Command. I expected this to toggle the discount on and off.

The problem
Instead of toggling, the discount still seems to trigger automatically whenever I add and close a ticket. Even worse, if I close the ticket and then remove an item, the discount remains and cannot be removed, which leaves me with a negative, unsettled ticket.

I’m clearly missing something in the logic, but I can’t figure out where. Any guidance would be greatly appreciated.