What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
As I can understand your question, you need to show your customers the fees that will be charged per transaction.
Based on the documentation provided on the other thread, you could do the calculation and just display it in the form without passing it to the payment field.
To do so you will need to perform some calculations on your form, here's a guide that will help you with that: How-to-Perform-Form-Calculation-Using-a-Widget
This is the only way that I can see to show the additional fees charged from the Square ends in the form directly.
Hope this helps.