5354 more costly? Well, if you look at pilot productivity then as long as the pilot force fly close to 900 hrs per year then the amount of days off vs duty days is irrelevant. However, I believe a fixed roster requires more/better planing and roster stability to work, it gives the company less flexibilty ie when things go wrong - bad wx with lots of diversions, crew running out of hrs or a/c going tech - then fixed rosters gives less options for the company.