Whatever floats your boat...
To me it's pretty obvious that the EU reg speaks to "a flight" in reference to compensation for certain inconveniences. In the old paper days, a coupon was indeed a ticket for a specific flight - you could throw away the rest of the "ticket" and that coupon would get you on the specified flight.
But if you want to tilt at windmills go right ahead. I do find it ironic that those telling others to do this and that based on nothing but what they think words on a piece of paper mean never say that they've done what they extoll as right and were successful.
Jim