I've noticed the last 2 times I've flown with KLM that it no longer seems possible to check the seating plan again, using the blue self-service transfer machines. Previously, you could look at the seat map, change your seat if you wished, and re-print the boarding pass.

Now, for me at least, it will only print out a "Flight information" chit, showing the passenger name, flight number, destination, boarding time, departure time, and gate number.

I don't know why, but I used to nearly always check the seating in the lounge shortly before leaving for the gate, if only to see how busy the flight was going to be.