Maybe a bit of a mix up in terms here. Airlines such as TOm who flew the 737 / 767 and the airline mentioned above flying a 737 / 320 are operating 2 types (allowable under EU-OPS 1.980 -reference from memory so may be a touch out). O2T means that you still need to do the recurrent training / checking as per FCL / OPS for each type.
MFF is when you get credit so can reduce the training / checking. This is like flying the 330 / 340 and i guess 320 / 330.
Edited to say that 757 / 767 isn't O2T or MFF as it is a common type rating (like the B737-300 and B737-800)
Last edited by Winston; 12th Jan 2013 at 21:29.