Compared to VGC:
|Console||VGC sales||Sony sales||Difference|
|Playstation 4 (not final)||94.90||96.8||-1.9M|
Ofc PS4 still has units in transition and on shelves so i think the 2M difference are pretty fine.
Overall VGC has a tendency to overestimate Playstation hardware. And my guess is that its the same for the Vita which sold so bad that Sony does not want to disclose numbers.