Exclude 'invisible' fields from count

My pdf form has 80 fields. Adobe (jso), however, tells me I have 460. Here's the code:

   Set jso = PDDocument.GetJSObject

   fcount = jso.numfields

When I press 'Tools | Prepare Form', Tab Order view, 80 fields show in the 'Fields' section of the screen.

When I press the 'A-Z' button in the Fields section, all 460 fields are listed. Those 380 new items all begin with an underscore and seem to be categorized with a parent and several children. They do seem to parallel the 'real' fields. None of them allow a right click for me to see their properties.

What are they and how can I ignore them in my code? Since I am required (without your answer to my question) to cycle through 460 fields instead of 80, I am really bogged down as the 'invisible' ones are processed.

BTW, the 'invisible' in the title to this question has nothing to do with the 'hidden' property available with the 'real' 80 fields. These are actually invisible fields that cannot be touched.