Hena,
Sounds like you are clear now. To recap, neither character has Commander.
They are essentially the same, but the Shas'o has the reroll ability - and costs more.
Supreme Commander normally comes with three things
reroll
commander
leader
Tau supreme commander just replaces commander with coordinated fire.
If one is familiar with Supreme Commander, the notes text under Shas'o is intended to be a pretty basic 'swap a for b' situation. I don't think we want to create special rule text unless absolutely necessary.
Cheers,