inglés al español Jurídico/Patentes Derecho: contrato(s) contrato de compraventa de participaciones

No comprendo muy bien el significado de la última frase de este párrafo:

"Except otherwise agreed between the participated company of xxxxxx and the companies according to the contracts described under provision 1.1, the companies and the buyer commit themselves from closing onwards to cease any advertisement, publicity, etc. using the trademarks of the seller and participated companies and to cease in the use of any reference to the position of the seller as shareholder except from a restricted use of existing materials (such as brochures) for a period of 12 months following closing. Provided it is caused by business reasons, the 12 months period shall be automatically extended to 24 months provided no party has terminated the restricted use with a notice period of one month until the end of the extended period"

¿dice que solo por razones comerciales se podrá prorrogar el periodo de 12 meses a 24 meses si ninguna parte ha cancelado el uso restringido un mes antes de que se prorrogue el plazo de 12 meses?

Gracias anticipadas por vuestra ayuda