Custom domain instructions - SSL not supported?

https://www.jotform.com/help/144-How-to-use-Custom-Domains-with-Jotform

On the above instructions, it says "HTTPS (SSL) is currently not supported."

I don't understand this statement.  If I follow your instructions for a DNS change, doesn't my Jotform form which begins with "https" remain as https or SSL protected? 

It means that you can not use custom domains on HTTPS forms, only on HTTP forms.