I've been keeping track of KL641 as an example. Checked ExpertFlyer & the KLM website on October 8th: Every single flight from 08-24 October was either bookable for PE, or, had PE fully booked. Between October 8 and today, a total of 3 flights were actually operated by a 787-10 having PE. Four flights operated by a 787-9 or 777 not offering PE. So less than half of the flights that were sold with PE, did not actually operate PE.

IMHO KLM is showing bad faith by doing this. These downgrades are not because of IRROPS, but rather they are purposefully selling PE (knowingly that they will substitute aircraft if they need a hand full more/less seats), and then downgrade pax. In many cases very last minute. Honestly, if I had realised this was the case, I'd have booked another carrier for my flights next week.

If I would be in the situation of being downgraded (And I very well could be, having two PE flights scheduled next week) I'd do anything to get compensated fully. KLM is, imho, dishonest by selling PE knowing they won't be able to honor those reservations on more than half of these flights. Or actually they may be able, but they choose not to.