User blog comment:Hayashi H/Fall 2015 Fleet Setups/@comment-26486243-20151202064045

Just dumping some Arashi calcs I made for chat, but which people might want to consider. Source: poi-statistics. Since poi-statistics does not declare the number of A ranks done specifically, the only way was to find the total number of attempts and deduct off the number of S-ranks and null drops (C-rank and below always drop null). While this isn't a perfect analysis, since the number of B-ranks is small, it's not going to significantly affect the percentages - just take notes that all A-rank drop rates will be slightly higher than indicated, since B-ranks don't drop Arashi. Also note that this does NOT account for the number of times fleets were turned back. If we were to use the number of times people sortied to node G as a proxy for the number of attempts at boss clears, then: Note also that discussion completely ignores the fact that the fleets which challenge Easy are generally less well-equipped on average than those which challenge Hard, and Support Expeditions are called more often for higher difficulties than lower difficulties. For instance, given the comp I'm using, since I have a 100% rate of reaching the boss, my overall drop rate per sortie is going to be 1.99% without support expeditions - which already eclipses the drop rates of Arashi WITH support expeditions on average.
 * Easy: 57575 (50654 reached boss, 88.0% rate) - Overall drop rate per sortie ~ 1.75%
 * Medium: 25372 (19980 reached boss, 78.7% rate) - Overall drop rate per sortie ~ 1.57%
 * Hard: 175559 (122,100 reached boss, 69.5% rate) - Overall drop rate per sortie ~ 1.95%

Based on all of these factors, I'd conclude that farming Easy or Hard is up to the user, but farming Medium for Arashi is always a bad idea regardless of the fleet used.