> the “4 10s” concept is also a bad idea that permeates the defense contractors.

If you're doing work on a cost-plus-fixed-fee contract (which many software development efforts are) then you have to count hours anyway because you get paid based on what you bill. The fact that nothing substantial gets done in the additional 1-2 hours a day is immaterial because these arrangements are really just fringe benefits in the form of additional time off for employees. As a practical example: people working "9 hour days" with mid-afternoon on-site customer meetings and a half Friday from home certainly aren't fitting 40 hours of productivity into their week and nobody cares - everybody gets paid, the job gets done (for some value thereof), and millions of Americans stay employed. One might even argue that this is a feature since working less efficiently means more billable hours to the government and a larger economy.