Question about digitec connect 12-month basic mobile subscription voucher

I have an understanding question: In a Family + Friends package with 4 people, the basic fee of 25.- includes 6GB. Do I understand correctly that with this voucher, this basic fee is waived for 1 year, but you can buy the 1GB additional package for 6.- per month for unlimited internet? So in the end you only pay the 6.- per month for the additional 1GB in the first year and have unlimited internet.