Is a 12-Month Addendum Period Acceptable When the Norm is 3 Months?

The message below is self-explanatory. I am requesting you to kindly advise.

Addendum Usage Period

(Addendum can be used as a tool only for a shorter period, i.e., for a month or a maximum of 3 months. However, this addendum is for a period of 12 months, so we should not consider it.)

Thank you.

My query was, what is the maximum validity of an addendum.

Regards,
Raja

Addendum Validity in Contracts

An addendum is a part of a contract and remains valid as long as the contract period is in force, provided it is accepted by both parties.

Regards,
Pon