I did a bit of research...
2/1's in the old frame
2/1's in the new frame, pre-2012
2/1's in the new frame, post-2011
1/2's in the old frame
1/2's in the new frame, pre-2012
1/2's in the new frame, post-2011
1 cmc 2/1's in the old days used to come with a disadvantage, the only exception...