Calculation Field won't go to zero when changes are made.

I have a field that is calculating the price of a party pack but I've noticed that if I choose one party pack and then change my mind to another one then it totals the price of the 2 different choices so the field isn't return to zero when you uncheck a selection.  I've tried some different conditional formulas to force it back to zero but that doesn't seem to get it to work either.  I'd appreciate any help.

https://form.jotform.com/62825691982166

The value inside the "Number of Kids Party Pack" field is not being cleared when they are hidden, which is why the Total Price still shows the total price of the two choices even when only one is selected.

To resolve this issue, please follow the steps below:

1. Open the Preferences wizard

2. Click Advanced, then Show More

3. Scroll down until you find the "Clear Hidden Field Values" dropdown and set it to "Clear on Being Hidden". Save changes when done.

Here's a demo form so you can see it in action: https://form.jotform.com/62870212026952 

If you need further assistance, please let us know.
Regards.