Hum, those numbers would be a tad bit too high, because the price drop was just at E3, which was at the end of Mai. So, if PS2 sold through at the same rate as it did in April (218\'000/month), we can expect it to sell ~147\'000 until the price drop + the units sold after the price drop with the 5 to 8 increase.
Based on these numbers, we can expect a Mai sell through of about ~400\'000 to ~550\'000 units.