The Russians did that to cater to delays from India in the Su-57 program
Su-57 program was delayed, as India left the program after only investing little ~300million , while russia wanted India Russia initially requested $6 billion from India as its 50% share for final design and R&D.
The Su-57 was originally expected to enter service by 2015.
After delays
Service entry in december 2020,Now in 2026, they have little more than 40+ su57 in service, su57 with al51 still haven't been delivered.
SoKo did the same for KF-21 when the Indonesians delayed spending too.
Indonesia was from the start always a very junior partner.
The total program cost for the KF-21 Boramae project is estimated at approximately 16.5 trillion won
This budget is divided into 2 stages.
System Development (EMD): Approximately 8.1 trillion won.
Mass Production setup (Initial Phase): Approximately 8.4 trillion won.
Initially Indonesia's commitment was 1.6 trillion won for the entire project, less than 10% of entire project cost.
basically its tot cost being initially paid for, when Indonesia finally buys some numbers of kf 21.
But.
Indonesia has revised its investment to 600 billion won approx now.
Korea from the start was ready to bear vast majority of program cost.