You almost make it sound like Bristow management changed the contracts from from 8/4 to 7/5 then 6/6 out of the goodness of their hearts.
The only reasons for these changes were simply because:
a/ The clients stated that for health and safety reasons, 8/4 was simply too long to be working in Nigeria which is why their employees were already on equal time and
b/ Bristow was losing too many employees either through sickness, stress or simply people getting a better deal elsewhere.
Nothing to do with clients stating anything about health and safety, it was simply a case, as it is now, of supply and demand. Other operators were offering better rotations, pilots were leaving, there was a shortage of qualified pilots willing to go to Nigeria, so better deals were offered. Now it's the opposite. Supply and demand. If the pendulum eventually swings the other way again, rosters will probably change.