The first NIP, to the Registered Keeper, is the only one required by law and so the only one subject to the 14-day time limit.
The NIP you have is provided for courtesy only and also because it is produced by the same system which produces the accompanying “request for driver’s details” (and is usually printed on the same sheet of paper). That request is not for courtesy, and it is not subject to any time limit. You must respond to it within the 28 days allowed.