The style of the accomodation will not matter. If you are in an entitlement above that of your rank, through your own choice, you will pay extra and grade 2 accom - unless the Unit have put you in SSSA and that is the only SSSA available. If this is the case then you should go and talk it through with the RAO staff. JSP 464 Part 3 is the relevant JSP that can give you direction - you can access from work or on armynet.
i hope this helps - feel free to pm me if you want to ask any other questions.