From what I understand, there's no pay scale based on longevity. Year one FO pay is the same as a year 3 FO.
If you are referring to tax withholds on your monthly check, there are non. Medical insurance for you, spouse and 3 kids is fully covered by the company also.
Company advertises 39,500 AED per month based on 80hrs of flying a month. This amount includes basic salary, flight time pay (80hrs), transportation allowance and housing allowance.