Last Monday I flew my first KL flight since signing up. It was the first leg of a roundtrip. The extra 5XP credited directly, thus earning 10XP for the first leg. With 5XP for the return leg (in a few months) that will be 15XP total.
I now booked a last-minute flight for this weekend. And this also shows that I'll earn 15XP instead of the regular 10. While my other (older) bookings do not. Curious to see if I'll indeed get that extra 5XP once more..
The KLM flight hasn't posted to Accor yet though, so I'm not yet able to calculate on which part of the fare the accor miles are calculated.