I read it earlier on your blog about the plans to start F service to AMS. That's why I'm a little bit surprised they didn't sell F, but on the other hand I have no clue how they can sell their F seats on a low yield route as AMS.
I thought the refurbish 77E are specially designed for the Dutch market, lots of Y seats and a few J seats. With the change of equipment in the high season, they offer less Y seats (77E = 245 and 77W = 228). I know the fights between SIN and AMS are most of the time fully packed, but can they really fill 42 J seats on their 77W on this route?
I think if SQ start F service to Amsterdam, it won't be long, their prices will be too high compared to Emirates. China Southern offers on the route CAN-AMS-CAN and PEK-AMS-PEK F service price +/- 8200 EUR and lets be honest, China Southern is not a world class airliner.
Let's see what happens...