Upgrade to World Business Class
Like to enjoy extra comfort, access to our lounges, a sleeper seat for utter relaxation, a delightful three-course menu and more? If there are still seats available in our World Business Class before departure, we might offer you the possibility to purchase an upgrade during online check-in.
You can upgrade your seat, depending on availability, at the ticket office or in our KLM Crown Lounges at Amsterdam Airport Schiphol. You can even ask about an upgrade after boarding.
At the ticket office, you can use any means of payment, including Flying Blue Miles. In the lounges, you can pay only with Miles. Once on board, you can purchase an upgrade with your credit card or by paying cash.
I saw this recently, too, and have seen some mentions in various threads here over the last while, where people seemingly in economy class have been offered an upgrade during the checkin, but it typically seems to be for what the posters viewed as an extortionate fee.
I've not done enough longhaul on KL to have any direct experience - and it became apparent on my last TATL that the entire plane was full, so I didn't enquire at the desk...
I'm sure, anyway, that they would only upgrade at the ticketholder's request based on the fare class. However, I assume that, should the OLCI offer a paid upgrade, that it wouldn't be so choosey about the fare class your ticket was booked in. Whether this would then effect the proposed price or not, I do not know.