Amazon Pay – why warning on no existing merchant account?

I’m a professional seller on Amazon.com and want to use the Amazon pay woo commerce plugin with my site. As I am looking to configure it, it has this warning:

“Important note, before you sign up: … Use an email address that you have never used for any Amazon account. If you have an Amazon Seller account (Selling on Amazon), sign out and use a different address to register your Amazon Payments account.”

I can’t understand why this would be necessary, as all my crucial information is in my amazon merchant account so sign up *should* be a breeze.

Why are they warning me to start making amazon business credentials from scratch rather than use my existing information?

Just wanted to inquire as Amazon can have some strict policies… but I can’t see how this would imperil my main email/sales channel. Please let me know if this warning is still valid or not.

Thanks!!