As the doc says all locked crv must have the same ... @curvefi

Answer: The expiration date for all locked CRVs must be the same in order to ensure that all CRVs are valid and secure. This means that when adding or extending a locked CRV, the expiration date must be the same as the other locked CRVs. This ensures that all CRVs are valid and secure, and that no CRV becomes invalid or expired before the others. By keeping the expiration date for all locked CRVs the same, it also helps to ensure that all CRVs can be used for their intended purpose.

you'll add and extend and yes