Thanks for the input, guys!

It appears that I have two different fares. When I log into checkmytrip.com, the fare againts LWO-FRA is "Economy restricted" (though the booking class is Y). The FRA-KIX is shown as "Economy Flexible". As of today, the reservation has not been paid for and ticketed (the Embassy told that the MFA of Japan would do it sometime next week). When I asked them whether they could buy a roundtrip in Business class (given that it is cheaper than flying Y one-way), they told me that the T&C of the Program allow only economy class travel...

Hmm 699 euro. Well, for a student, it is a bit too much... From the info that SmilingBoy provided, can I infer that that economy is overbooked or just completely sold out (or does it mean the same)?

Thank you!