One Japanese estimate for Build + Maintain 10 submarines in Australia

S has made an interesting commentas follows:

“[S] analyzed cost of Soryu based on budget, and [S] concluded that Australia can build and maintain 10 submarines for 30 years (total cost 1,600B Yen) [= approximately A$20 Billion] under a proper management system. 

Modification cost of 29SS to Aus 1 [per submarine for Australia] is 5 B Yen [A$62 million].

Adoption cost of US combat system is not high.

Premium [build] cost in Australia is 10B Yen

30years- operation cost is double of building cost.

Life cycle cost for 30 years = {basic cost (65B) +US combat (0B)+ modification (5B)+ premium (10B)}x 2= 160B Yen [= approximately A$2 Billion per submarine]

[S] January 18, 2016 at 1:15 AM”

The figures above in square […] brackets are in Australian dollars where

1B = 1 Billion Yen = 12.4 million Australian dollars (A$) at January 18, 2016 exchange rates.

Building and maintaining 10 submarines for 30 years (at total cost 1,600B Yen) [approximately A$20 Billion] appears to be an attractive all up price.

1. However if:

Building cost is {basic cost (65B) +US combat (0B)+ modification (5B)+ premium (10B) = 80B Yen = aproximately A$992 million 

and 

"30 years operation cost is double of building cost" = 2 x A$992 million = A$1.984 Billion

Then wouldn't total for "Building and maintaining 10 submarines for 30 years" = A$992 million + A$1.984 Billion = A$2.976 Billion per submarine = approximately A$3 Billion per submarine?

Making Total for all 10 approximately A$30 Billion?

2.  I assume that the Maintain costs would not include personnel costs for (Navy + Defence civilian) pay and updating Combat System costs? 

Pete