SubhamRanjan99
I could see that we can submit the application even without entering any GMAT score in the 'Test Scores' section. So I think entering the maximum scores of GMAT is not mandatory and those who have not entered scores now can provide them through the link that ISB will send next (about which they mentioned in the last mail).
Please correct me if I am wrong.
If you had not entered scores before receiving ISB's email for date extension, you will be able to leave them blank. Entering a full score is for the people who had entered some scores previously because resetting the scores is not possible. Hope this helps!

Oh, I entered full scores after seeing comments, even though I hadn't entered the scores before.
Hoping it's cool.