You'll have to ask Microsoft why they schedule their PR in such a way. Again, most companies release sales PR late in the day, similar to how companies release their earnings reports either before or after market hours, not during. NPD releases after market, etc.
But again, I don't know what you're arguing here. Microsoft knows their sales precisely. They're not on the phone with every mom-n-pop getting updated tallies, they know they presold the majority and walk-ins will take care of the rest. Shipped = sold. If not, they have a problem.
Is it really about the comparison to PS4? It's ridiculously unimportant. It's a shipping battle. If Microsoft thought they won that battle in North America, believe me, they would have reported it. But regardless, it says nothing about demand. Repeat it: it says nothing about demand. It says nothing about which system is more desired. The numbers are absolutely supply constrained. Do you or do you not agree? And if that's the case, what's the point in arguing about it?