These additional prototypes - whether 2,3 or 4 were for speeding up the FOC by testing all those sub systems like avionics - AESA radar, EW suite, weapons integration, etc & sticking to the strict time schedule of 2028-29 thus avoiding the tedious trials the Mk1 underwent which was seemingly forever & interminable .The Key word from IAF chief interview is " Production Model "
So the question is How many years for the Journey From
Prototype to Production Model
MK 1A took 6 years from 2016 to 2022 to become a Reality
As we have recently learned that One Prototype has begun Test Flying
Serial production of MK1A will begin in 2024
Where are those avionics? What will you do by producing those additional prototypes now?
As of now the ADA / HAL's time schedule which seems delayed by a year is to introduce 1 prototype of the Mk-2 in 2023 , complete taxi trials before moving to air trials by 2024. Whatever prototypes are planned would be post 2025 when they're achieved some validity of their design. What's the point in producing 3-4 prototypes now when neither your design is validated not the avionics ready?
Having Said that, the moves of the MoD GoI & IAF should be carefully watched. The projected T/L were very aggressive to begin with & left no room for error which isn't how these programs are typically run especially when you don't have an experienced technical consultant like KAI does LM which can greatly cut down the lead time for development.
Some slippages are par for the course except that production must commence by 2030. Anything beyond that would be delaying an already delayed product with a limited shelf life to begin with. Let's see what happens.