The Preacher is somewhat confused as to the definition of elastic limit.
Material stressed to a point below or equal to the elastic limit will return to its' original dimensions after the strain is removed. As soon as stresses exceed the elastic limit, there will be a permanent deformation. This permanent deformation does not require a defined 0.2% deformation to meet the definition of exceeding elastic limit. If the permanent deformation is even one half of that, or one tenth of that, or any measurable amount whatsoever... then elastic limit has been exceeded.
The Preacher is confusing and conflating the definitions of elastic limit, and yield strength. Simply put, elastic limit is the measure of the point of maximum stress where a material returns to the original dimension after removal of that stress or strain. The instant that permanent deformation occurs, elastic limit has been exceeded.
