Two screens and you clicked on KLM and then AF right after that without waiting for the KLM confirmation?

Update: I did a test run even though I'm a month away from check in and was able to add SAF on klm.nl, airfrance.nl, and klm.be. I assume that it's fine for me to buy 3x SAF?

Also, does it matter if I buy the 3x SAF now or at check in?

Thanks so much, and sorry for all the questions!