Why are you mentioning Amazon .... they don't show sales numbers.
PS4 offer 4 version of their consoles compared to Xbox compared to 6+ version of the Xbox one consoles.
Who does show sales numbers for Xbox? All we have to go on is Amazon US positions. This isn't new.
As for PS4 - I've not made a single comparison to it. I'm talking about Xbox One 2018 vs 2017 (since that's what you were talking about). You expect a 1.5m uptick and I don't see it happening.