The attendant does not know the details of your membership but if s/he recorded it as "two guests" rather than "one cardholder plus one guest" the billing could be incorrect.
I got burned by this a while ago at the DL Sky Club in JFK (back when they participated in PP). I was there by myself, but the attendant indicated "1 guest," probably not understanding that the column was meant to record
additional guests beyond the cardholder.
When I got the $27 charge, I asked Priority Pass to look into it. They provided a copy of the form and said it clearly showed I had a guest and refused to make any adjustment.
I understand the rationale for not issuing the refund, but they acted as if I was trying to perpetrate a scam, which I did not appreciate.