It has to be, because that's how it's sold.

Briefly checked the Brother website because I also need a printer. Website: The promotion runs from 1 October 2019 to 31 December 2019 and is valid from the date of purchase as shown on the proof of purchase.
Redeemable within 30 days from date of purchase.
Digitec will rely on the manufacturer and will certainly not pay the 150 from petty cash.