Overtime starts after 80 hrs in calendar month
Overtime rate Basic pay
------------- = $ per hour. E.g. 7500/80= 93.75 per hour
80
If your rotation starts on 1 st of the month then in 25 calendar months you can fly 120 hrs and get 40 hrs over time. Legally not possible every month do the math.
You can get overtime every month if you want to fly like crazy. Ethiopian airlines does not mind ( they will love you ) and the CAA looks the other way.
And right there is the reason for the slow motion taxiing and interminable wait lining up while everyone at the holding point wishes they'd get a bloody move on.