Grasta, that scheme sounds reasonable and workable. I will say that after many years of dealing with PT Central Kuta, I would trust them with this sort of arrangement if unable to have an account in another way. Their reputation has been impeccable and I’ve never heard of any expat having any problems in dealing with them. Thanks for explaining how they work it.
A similar scheme works within most banjars, that being the so-called community banks. With this arrangement, the community bank also has one (or more) master account with a major bank, but issues passbooks in the name of the village based account holder. Those accounts can be issued to foreigners residing within that banjar. Checking accounts are not available, but they are convenient for depositing IDR at reasonable interest rates, and one is also helping out the local banjar.