Prior to MDC (late '90s), QF crew were regularly doing 21:30 duty hours for 8 hours pay over two calendar days. I recall eight week rosters where I had 18 days off and got paid 132 hours pay (min guarantee as it was back then). The duty hours were astronomical but with long transits. SYD-MEL 2:30 doing nothing, MEL- SYD 2:30 doing nothing, SYD-MEL. 4 hours pay.
With 5:10 per day and then 5:30 as MDC, QF has managed to increase the utilisation of crew significantly to the extent that there are now many trips where the trip credits exceed 5:30/ day. Good for QF due to high utilisation. Good for crews due to more time at home.
To give you another example, in about 'the early naughties, I was doing 140 stick hours for 245 duty hours (and 172 hours pay) and getting 22 off every 8 weeks. Now I do (or did.... don't do those hours anymore) about 165 hours (175 hours pay) for 240 duty hours and get 25-26 days off.