Jakab Abraham Schwartz - Schwartz vs. Schwartzkopf

i see along this family tree that the surnames Schwartz and Scwartzkof are interchangeably used. Some descendants surnames are Schwartz and others are Schwartzkopf.

These names show on Ujfeherto (Ratzfert) records but there is a missing link here to support that this can be done. that is, how have you determined that a person with last name Schwartzkops is associated with the Schwartz family member? Are they really the same persons? Is it based on documents or family lure?