I believe that's correct. Business version of Priority Pass didn't include a complimentary guest, but personal Priority Pass does. Not all supplementary cards are eligible for Priority Pass (on personal Amex it's primary cardholder + 1 other, business might be primary cardholder only). But you can still use all supplementary cards to access lounges that are entered by presenting the physical American Express card rather than the Priority Pass card (Centurion, Plaza Premium, Lufthansa, Delta etc).