I flew KLM metal (747) on a 006 ticket from SFO to AMS (and onward to SVG) at the end of July. When I checked in for the first flight, I was redirected to the KLM website. I changed my seat from economy to business class and they asked for $600 Euros, which I was happy to pay. On my return, I will stop at the KLM transfer desk in AMS and request an upgrade. Past experience suggests that I will pay about 300 Euros and 20,000 skymiles.