Its not always a S, if fathers firstname ends with a S then sometimes only the Z is added, for example firstname Claas, the Lastname for the child good be Claasz.
Sometimes the X is used, child of Heyndrick : Tanneke Heyndrickx
An other problem is that sometimes during lifetime (in my family between 1600 and 1700) a kind of extra lastname /nickname was added.
For example de National naval hero Michiel Adriaansz de Ruyter. Fathers name Adriaen Michielszoon, LNAB Michiel Adriaensz . In liftime the name "de Ruyter" is been added. His children were given the surname"de Ruyter"
Also Lastnames can change. In my case of fathers line: Meeuwsz, Danielse, Danielse van Bilsen, van Bilsen, van Belsen and at least van Belzen. This in a period of 400 years.
So I think its not a good idea because its to complicated.