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.
I could not replicate the issue. As per the test , I found the sliders working and the results calculated accordingly.
If you still don't see the results as appearing in the video below, I would suggest you to clear the form cache and the browser cache and check again.
Browser cache : http://www.refreshyourcache.com/en/home/
Form cache : https://www.jotform.com/help/229-How-to-Clear-Your-Form-Cache
Let us know if you still face the issue.