Hello @Poggy, your calls to Swiss are included if you have a "Onbeperkt bellen" subscription. See https://www.kpn.com/bellen/opties/onbeperkt-bellen.htm for more info. If you click Naar welke landen kan ik onbeperkt bellen met BelOnbeperkt Altijd? then all the included countries are shown. 
This is information for a landline

For mobile: If you have a mobile phone with the onbeperkt bellen subscription Swiss is also included. We included Swiss because while not in the EU it is still a country in Europe

Is this about a landline or mobile?

it is about a mobile with onbeperkt bellen.

I was told that if i ring Switzerland from Holland ( ie. a Swiss number whether mobile or land line) then i will have to pay for the call.

All other calls in Europe are “free”

If I ring someone in Switzerland with a dutch mobile and dutch mobile telephone number  - then it is free.

So what is correct?

I just clicked on the link you gave me  - now I see something new for me “Bel Onbeperkt Altijd”.

This seems to let you ring the whole world almost “free”

Is this new and different from the Europe model?

The first part of my post above is information for a landline. I understand your question is for a mobile number. 

For mobile: If you have a mobile phone with the onbeperkt bellen subscription Swiss is also included. We included Swiss because while not in the EU it is still a coutry in Europe