An 8 p.m. departure does not mean that boarding will be delayed past he usuall,11:30 or so, unless the ship arrives later than normal..BTW you cannot begin checkin 120 days prior to sailing it is 21 days
All aboard times at non tender ports of call is usually 30 minutes prior to departure. The description on line is a bit deceptive in that the 2 hours is only for initial embarkation.