I run 2 120 fisherman on all facets, tramell, felucca, tok, using FAF a lot of the times, when i run them both i see a difference in the rates, usually 1 ancient out of 25 MIB. the other fisherman gets 1 out of 35 to 40 usually. I did get very lucky yesterday and pull 4 ancients in under 30 minutes, i was going WTF.. that was in t2a.
I can honestly say i am sitting on over 300 MIB right now and about 20 are ancient.