flexifare

What is Flexifare? To quote the Aer Lingus site:
[FONT=Arial, Helvetica, sans-serif]you can change the date and time of your flight up to two hours before your flight departure without paying a fare differential or change fee.[/FONT]

Yippee, I thought!
But when I went to the site to check it out I found the change fee is €35. Can anyone make anything of this please?

Change fee will be charged if your existing booking wasnt purchased as a Flexifare. if you originally booked a flexifare ticket, when you go to change the itinerary, change fee should be zero...