@isie: i think it because you are locked into legacy subscription. Before netflix created the SD and HD accounts the cost was 7.99 for 2 screens and HD. When they upped the price for the HD and introduced SD only accounts they locked their earlier subscribers into a legacy pricing. The plan pricing remains so until May this year where those subscribers need to pay what the rest are paying.
Note: Check account details on your netflix account
Note: Check account details on your netflix account