Question about NortonLifeLock 360 Deluxe

That would not be possible. The licence is valid for a maximum of one year and during this one year you could operate up to a maximum of five devices. That means it could also be only one device. After one year after the licence has been redeemed, it expires regardless of whether only one or a maximum of five devices were operated during this period.
With kind regards.

You cannot activate all 5 licences at the same time, as Norton calculates per licence number, i.e. one licence activated = 5 devices / 12 months, and 5 licences activated = 25 devices (5 x 5) / 12 months and not 5 devices / 12+12+12+12 = 60 months. Let the old licence expire and activate a new licence on the last day.