Hi CAC,
I can give a broad generalization of how I think IOC is bound by this bidding process. To make it short and sweet, I believe that IOC can do whatever the hell they want. Meaning they could extend the process another month, cancel the bidding process entirely, change the specifications of the selldown (only selling 15% now), etc
HOWEVER, this is extremely unorthodox and is only done in exceptional circumstances. My personal opinion is that your scenario WILL NOT happen. I also believe there have been multiple rounds of internal bidding with the results being communicated to all bidding parties. I believe that has produced an acceptable bid for IOC. With an acceptable bid, we finally see that final (take it or leave it) deadline.
It would be extremely bad karma with the bidders, shareholders and government to change the process now and I would be extremely disappointed if that happened.