Originally Posted by edi-traveller
This is what I have found - selecting Economy Lowest and upgrading allows a cheaper CE fare than selecting Business Lowest.
You can see it in the fare hierarchy below. If you select Economy Lowest and upgrade you get the IEULGWUK fare. If you select Business Lowest you get the IEUNBA fare.
Just trying CAG however, I see no ?EUNBA fares (for I/D/C)
After IEULGWUK/DEULGWUK it goes to CEUCLGW and then JFLNA/JFLRT