Where else would I be, but in transit
kuroko is the fares expert, and unfortunately the only definitive indicator of EK fare group is the 4th letter from the right as he says.
In
general you find that:
Flex Plus: (first) F (business) J (economy) Y, E, R
Flex: (first) A (business) C, I (economy) W, M, B
Saver: (business) O (economy) Q, L, T
Special: (economy) L, T, V, X