Hi @SteveJLV welcome in the plugincafe community,
I would like to point you to some rules:
Read Before Posting. Nothing wrong here, but just in case.
Q&A New Functionality. I've setup your topic correctly.
As you already figured it out, you never assign a new value to the variable. In Python, everything is passed by value by default in 90% of the time.
Meaning when you do x = y will actually copy y to x, so afterward if you do x + 10 it will not affect y value.
If you have more questions, don't hesitate.
Cheers,
Maxime.