What is the difference between a single phone call from Santa and the collective version?

In the singular version, Santa will call the child and address him directly, eg "Dear Adam". In the collective version, it depends on the number of recipients. When choosing 2 or 3 addressees, Santa will say their names over the phone. In the case of the option "over 3 children", Mikołaj will address the recipients with the words "Dear children".