This is just a consolation prize -- a good will gesture for family of Plats. Remember that you were demanding an additional 300 Euro each, and my arithmetic says you're 3 x 200 = 600 Euro short of that.
The agent might have been wiser to say "300-600 Euro depending on how much later you arrive", etc., but you can't expect her to stand there reciting the entire policy manual while she's asking people to volunteer.
In the original thread, you admit that you were given an opportunity to board your originally scheduled flight when you objected to the "switch". You should count your blessings (to the tune of 1200 Euro = $1980) and move on.
The link to the original thread is incorrect. This is the orginal thread:
Bait and Switch