As always
Important to point out that overtime is based on rostered actual block hours only. i.e if you do a Doha return and have delays resulting in a 8 hour duty day, you will get credit for only the two block hours that were rostered.
There is no credit for reserve duties or simulator proficiency checks (4 days every 6 months). There is no credit for leave or ground duties. i.e you can have 2 weeks leave, then fly 70 hours in the remaining 16 days and there will be no overtime.
When operating as a line pilot, ground duties etc are not a big factor as there are only a few of these each year (probably around 10 or 12, including sims) but reserve duties are a big issue. In theroy the company can fly you up to your overtime limit, then put you on reserve for the rest of the month and you will not receive any credit for the reserves. I dont know if this actually happens, but the rules allow it. In fact they actually encourage it.
like most companies i suspect. You have to look fairly closely at what is actually happening to work out how much you are likely to be paid for a normal months work.
In the entire time I have been here (between 6 and 7 years) i have probably done maybe 4 or 5 months of overtime (777). I actively avoid it, so it probably isn't representative, but that is how it has been for me. Having said that, i have worked many months where i was right up to the overtime limit, but didn't go above it.