Multiple choice summing not working

Hello, I have a question regarding summing the calculation values of a multiple choice list. I found this thread which I think explains pretty well what  want to do: https://www.jotform.com/answers/700441-Feature-Request-Multiple-Calculations-In-Same-Field

I'm talking mainly about the final post in that discussion, I want to make a form with multiple choices that will sum up their values just like on the example, but it seems like the sum is always 0, and when I clicked on the example in said post, it also seems to not be working (sum stays as 0 after choosing options). Could it be that this feature is not supported in the current version of JotForm?

There was an error on our end that caused calculations to fail.  Please accept our sincerest apologies.  This is now fixed and calculations should be working once again.  If the issues persists edit the form and save it.  Move one field to have it auto save then move the field back to its original position.  This will clear the error.

No worries David, thank you very much for your help.