We just got back from a cruise on the RC Radiance of the Seas. We ate 4 nights at a the specialty restraurants -- where there is a $20pp fee which is stated "includes tips". Therefore, we only ate at the regular dining room 3x. How should we have tipped? We tipped the recommended rate for 3 nights -- not for the whole cruse, since we only ate there 3 nights. Was this appropriate?