With a rigid 5/2/5/4 pattern it may not be possible to cover the flying program without employing additional pilots and flying everybody a bit less ie you won't do, and get paid for max hours. Company has the costs of additional staff.
If pilots could volunteer to work on their off days and get paid extra for it everybody wins. Those who want more money get it, those who prefer the time off can have that and the company save on additional staff.
