PS4 and X1 shipped nearly 30 million consoles at the end of 2014 according to AMD

[thismeintiel]

Yep, if those numbers are accurate, XBO is definitely overtracked. Sony probably shipped 19M-19.5M LTD by the end of last year. This leaves less than 10.5M-11M SHIPPED for XBO. VGC has it at ~10.8M SOLD. So, probably 500K-1M overtracked.