There really isn't enough data to make a statement like this. It's also way too broad because while it might be true for some multiplats it's certainly not true for all or even most multiplats.
Only really Ubisoft gives platform breakdowns for their revenue and PC was the biggest platform the last two quarters, one of which The DIvision 2 launched in. For Ubisoft atleast PS4 is never even close to being more than 50% of the market. It's currently not even their biggest platform.
Yes we do. We have month sales from EU and USA and even Japan.
Most multiplatforms sell the most on the ps4, Ubisoft is the exception in this last year/2 years.