Can't inline images but here:
https://i.imgur.com/vwsyX9A.pngTotal Armies:
206.533 + 59.946 + 135.21 - 1.004 = 400.685 B
Base Merc:
88.768/1.45 = 61.219 B
%
61.219/400.685 = 15.279%
In the end I was actually ~16b short after exhausting drafts. I accepted rafflebot donation of a FC and used 2 SAC + super FC to get 14B and finish to save me 24+ hours. The map had 2 SAC + 4FC so it worked out.