You are the Contract Manager for the Engineer in a highway project using FIDIC Red...

Each index or price applicable on the date 49 days before the expiry of the Time for Completion of the Works.

The current index or price.

Either the current index/price, or index or price applicable on the date 49 days before the expiry of the Time for Completion of the Works, whichever is more favourable to the Employer.

Either the current index/price, or index or price applicable on the date 49 days before the expiry of the Time for Completion of the Works, whichever agreed by Parties.