The bug in which html characters are displayed as squares/question marks in the Backend parameter editor makes this a huge headache when editing and nearly unusable. Depending on how many html characters and formatting changes you have made, you might have to reupdate 20+ fields in order to move one comma or space. If you don't reupdate these other fields and save, your clock will lose its formatting and become riddled with ASCII unknown symbols.
This bug needs to be fixed. I have hacked around it by using str_replace on the module parameters once they are loaded by the module, and using SPACE instead of etc. I wonder how many people have been unfortunately turned off this otherwise excellent module because of this very prominent bug.