You want to talk about flooding, talk about last year when 3.7m were on shelves. They could have spared a ton to Japan but didn't in order to perfectly hit their shipment target. They also shipped more last year's FY Q4, 2.9m vs 2.5m. Again imo to meet their FY targets.
I think sony made deals to ship to new countries last year, that why they were able to ship so much, this year they don't have that benefit.