means that you potentially have to keep twice as many spare parts. It means you need to have two separate training pipelines. It means two separate programs for MLU in 10-15 years time.
If only two then TNI already in relative good logistics situation for their situation challanges. Combination of budget opportunity, geopolitics logics (of Indonesian pov), local political balances, and changes on "taste", all are in play toward the lobbyist game.
During Soekarno and Soeharto era, it is more manageable as only one "taste" as final decision. Geopolitics also more straighforward. All changes when 'democracy' come to play. Democracy means more "taste" has to be manage.
Back to Submarine, sometime ago when he's still Defense Minister, Prabowo's come out on the concept tactical and strategic submarines. In sense from that point on, at least two type of submarine being sought. More litoral tactical and more blue water strategic ones. Many including me tought the tactical will be DSME 209 (batch 1 and 2), and NG Scorpene as blue water strategic submarine.
This then "taste" and politics come in. The electrical problem of DSME 209 batch 1, then being use by others (faction, marketing lobbyst, etc), to 'scuttle' DSME 209 batch 2. Use the chance on finding alternatives ranging from quality up to get better capabilities (thus more budget). This is where Italian U212NFS, DGK Midget, Chinese S-26, and Japanese refurbished Oyashio (toward Soryu standard) coming to equation. Not to mention ROK keep lobby to maintain DSME (now Hanwha Ocean) still in play.
So which one going to be use for this tactical submarine ? I honestly only can guess like everyone else. My prediction is whoever meet the budget and timeline.