I just got it straight from KDP. You can add up to 3 pen names in your Author Central account. Yes, everybody knows that. But what a lot of people don’t know right now is that you can have a total of 7 pen names on one Author Central account.
You have to contact KDP to add the additional 4 pen names.
You’d think they’d just code the page to allow you to do it yourself. Maybe that feature is coming someday.
It used to be if you wanted to add more than 3 pen names you had to create another Author Central account, and then you could add up to 3 pens there. And if you had more, you had to open another Author Central account.
I can see where newer authors could screw themselves by misunderstanding, and opening another KDP account and then boom, they get their account banned.