@ywu: a "full 40 hours of work" is a ridiculous metric to use. Even someone logged into a phone for 8 hours a day 5 days a week doesn't necessarily do "40 hours of work". I've worked here over 20 years and I'd wager I've maybe only put in a few 40 hour weeks that whole time.
That antiquated slave labor mentality needs to go. I had a former coworker who constantly complained about the overtime he needed to work. I did more work than him and had multiple hours per day of doing nothing. He was trying to look busy so he could soak overtime and buy more home recording equipment and save up for his next 12 month trip to India.
He thought I was a lazy bum, but people people would breathe a sigh of relief when they got me instead of him to work with. They knew I'd get it done quick and proper instead of dragging it out and making them unproductive.