The maths you are doing needs quite a bit of work.
You can't count the re-grading as further additions to his salary. This is payment for experience and additional licences. Go back 30 years and the lames got wage rises and as they gained licences additional payments.
All professions have a system of progression throught he ranks. When an F/O becomes a Captain he moves up in position but his base rises remain at the level his union negotiates.
The licence payments are reduced since the pay structure. They are capped as well but yes we may go up every 4 years. For every lame who progresses through his career to the higher levels and then retire, a new lame starts again at level 3.
The company are replacing high level retiring lames with the much cheaper lower level guy. Do some maths on the saving they make there Mr Filler.