Ancon

I know the gratuity charged for stateroom attendants is charged (per guest) based on two occupants per room. How does it work when the passenger is traveling solo? Princess is covering the gratuity, but are they paying the attendants gratuity for one passenger or two? I don't want the room attendant to be only compensated for one passenger when they ordinarily would be getting paid for two passengers (for the same amount of work). It is a 32 day cruise. Thank you for your responses in advance.