Slitherine

I am playing through the Brighton scenario from AO'40, and noticing something weird. My KMS Bismarck is attacking the HMS Hood. The Bismark has attack 16, defense 15. The Hood has attack 15, defense 15. And yet the Hood is going to get much better results than the Bismarck (prediction below). What am I misunderstanding, here? Or is this a bug?


(KMS Bismarck) attacks (HMS Hood)

Main Stage

Combat range: 2

Attacker's Initiative:
Base Initiative: 9
Attacker's Effective Initiative: 9

Defender's Initiative:
Base Initiative: 9
Defender's Effective Initiative: 9

Initiative Difference: 9 - 9 = 0
Units shoot simultaneously.

(KMS Bismarck) strikes:

Base Number of Shots (single entity shoots at max strength): 10
Effective Number of Shots: 10

Base Accuracy: 50
Bonus from experience: +10
Penalty from enemy unit's experience: -4
Effective Accuracy: 56%

Base Attack rating: 16
Effective Attack: 16

Base Defense rating: 15
Effective Defense: 15

Deflect/Suppress/Kill chances: 35% / 20% / 45%

Prediction: 0.945170 killed, 0.000000 suppressed

(HMS Hood) strikes:

Base Number of Shots (single entity shoots at max strength): 10
Effective Number of Shots: 10

Base Accuracy: 50
Bonus from experience: +10
Penalty from enemy unit's experience: -4
Effective Accuracy: 56%

Base Attack rating: 15
Effective Attack: 15

Base Defense rating: 15
Effective Defense: 15

Deflect/Suppress/Kill chances: 40% / 20% / 40%

Prediction: 2.240000 killed, 1.018349 suppressed