Would be very unlikely to overship 1M this late on the life of the console. Seems more like they reduced the forecast to keep certainty they will exceed as they have all years.
That makes no sense, you dont adjust a forcast down if you're currently meeting/exceeding your expectations.
We roughly know how the PS4 is selling in NA and Japan thanks to leaked/reported numbers. And they are down, more or less significantly from last year's numbers. Shipping the same number as last year, we can easily see that the shelves are getting full pretty fast. So they are currently selling below expectations in all likelyhood.
My guess is somebody wanted a neat 100M number to report in this quarterly fiscal report, even if that meant overstocking. At least for prices, in Europe, they are still unchanged, as high as ever (in the $329-$349 range). So I wonder what The Plan is, actually...