I still stand by my prediction.
As StarDoor said, if current trends continue Switch will be 20.2m and PS4 will be 13.6m. That puts up Switch by 6.6m. Now when you factor in both Switch's upcoming software schedule and the new hardware model, I think being 10m+ ahead is pretty reasonable.
I am still very confident in my 25m prediction for Switch. The only thing that can kill my "10-15m ahead" prediction is if Sony issues a major permanent price cut. Still no word if they are going to do this or not.