It's easy to say productivity relating any metrics convenient for me so productivity matches my expectations. Why don't they share their metrics. And even when they do, as I see Microsoft's vision is so opinionated, I would doubtedly believe on their methods for collection and accuracy.
Being realistic, whenever you work from home you are more responsible of what you do, so if you finish what you do in fewer hours but the "manager" gives you extra work because of his expectations from "work from home" where higher from the beginning, thus manager's expectations will always be higher than what is possible in reality