Form Calculation: Why the quantity changes when you click on the submit button?

Also, when they click submit, the calculations CHANGE. This is not good- can you help ASAP?

I have submitted your form twice, the first one I selected the PayPal option and the second one I selected to send the payment, both I could see the amount was not changed when I clicked on the submitted button.

Here is a screen-cast about it: 

Were you able to resolve the problem on your end? 

If not, please provide us more details about it and how to replicate it on our end, we will be glad to further investigate the issue. 

Looking forward to your response.