I suppose the problem here that management realizes that the "8 hours" of work are being done by most employees in 6. They then add an extra 2 hours of work to

I suppose the problem here that management realizes that the "8 hours" of work are being done by most employees in 6. They then add an extra 2 hours of work to make the new "8 hours". Thus incentivising the workers to come up with gradually more and more dangerous ways to save time if they want to go home early. And the workers who stick to H&S guidelines have to stay for 10+ hours.