Occupancy certificate terms in the Sale agreement or Construction agreement

Q: Hi,
How are the terms on Occupancy certificate mentioned in the Sale agreement or Construction agreement?

I am looking at purchasing an apartment from a fairly new builder (has done 2 small projects so far).
I asked for a term to be mentioned in the Sale agreement. I asked for the below two

1. That builder commits to providing Occupancy certificate within 6 months of possession of the flat by the purchaser.
2. That the last payment 5% (or could be 2.5%) would be made only after Occupancy certificate is provided by the builder to the purchaser

The builder is willing to provide '1' but not willing to add any clause that says what if the occupancy certificate is not provided within 6 months per the term '1'.
Is this good enough?

The project is on Sarjapur road in a area of over 1 acres.
The builder is confident of providing Occupancy certificate.
From where the construction is today (it's a G+4 with 2 Basement parkings), there seems to be no significant deviations.

Thank you.