Thank you @JamesM4
I watched the video and read the instructions.
No where does it mention how to create a new invoice that does not include custom fields. It seems you either can have them on an invoice or you cannot.
When editing your new invoice style, > content > chose section the custom fields are in > at the bottom of the screen is 'Manage custom fields'. When you click that, it opens where the fields are used. There is only one Invoice choice, not 'Invoice A', Invoice B' and so on which leads me to believe you either use them on an invoice or you do not.
(I have attached a file which shows what I mean)
