I've having a tough time with the ORAT and DRAT calculations for flotillas on page 13 of the annex.

For the 3.4" guns I'm assuming the 120 in there comes from multiplying the SU cost of the battery (20) by the size of the flotilla (6). But why is that not done for the 20" torps and where did 8 come from (total SU Cost seems to be 7, not 8 by my calculations). Also, where did the 2.5 divisor come from? Shouldn't it be a 0.4 ORAT divisor for a ship with hull size .5?

Instead of:

8 * (3+6) / 3 / 2.5 

Shouldn't it be:

(7 * 6) * (3+6) / 3 / 0.4 = 315

Base SU cost of the battery =

(3 * 1 * 4.25 * 1.6 / 12) * 1.8 = 3.06

which rounds up to 4.

The total SU Cost =

4 * (4 + 4) = 32

The total SU Cost with ammo of four =

32 * (4 + 4) / (10 * 4) = 6.4

which rounds up to 7, not 8.

Battery ORAT =

7 * (3+6) / 3 / 0.4 = 52.5

Also, about the DRAT. The last time I checked 6 * 12 / (6 - 0) * 0.5 did not equal 52.56.

Was this perhaps pasted with the 20" torps ORAT value?