User blog comment:Hayashi H/Max-efficiency Map-clear Formations/@comment-24689097-20151231051012/@comment-11937523-20160117205901

I have had the same problem as you for quite a while under similar circumstances: 8x level average CAs and totally miserable at 4-5. I immediately disregarded this formation and went back to FBB and slow BB for last dance night node. Last month I decided to try it again and interestingly with CAs at 90-95 I beat 4-5 with only one failure. This month even went perfect with the change to 1CAV 2CA 2CVB 1CV. I didn't sparkle anything during the whole course of this. And as for the sub sometimes you get D there is nothing you can do, though bringing Prototype Seiran did help a bit(maybe not true, i didn't record any data, just seeing less Ds). Also might be level problem since I use a 97 Chikuma. There might be a difference between 9x level 8x level where the difficulty of 4-5 lies and once you past the point this becomes reliable. Also worth noting is that I akashied the shit out of CA equipment, though the impact of that shouldn't be too large.

TLDR version: might be a level/ equipment/ RNG issue, I had the same problem but now it works for me