I work in IT, not a programmer, but let's say that is similar. I work majority from home, and I can assure you that I work less that 4h a day, even if in my contract I have to work 8h.
Although I'm doing this for a while, playing games, watch tv shows and so on during work hours, never no one complained and I was actually promoted recently.
Of course that I'm always on during those 8h with my phone near by in case of an emergency, but I realized that some of my colleagues work way more than me and no one realizes the difference.
Does that happens to you too?
I'm not bragging, I don't feel great about this situation, it's just the way it is.