So, I got my e-cert a few days ago and I was playing around this morning with some fares MSP-SIN (for example) in B class. Well, try searching for fares with the e-cert entered and then search without the e-cert. In some cases it's knocking off well over the $400 it states that should be discounted. In my sample itinerary, it nocked off about $980...

^ ^
I should note, however, that it does not appear to work for open-jaw type itineraries, but only A-B-A type itineraries. Has anyone else tried using theirs and found anything interesting?