This because the reality of manuscripts can become rather complicated: in a Ladino corpus currently being developed in TEITOK, there is the original orthography, and expanded form, and the normalized form in current spelling.
when various orthographic forms are exported, say the original as well as the normalized orthography, it becomes possible to use CQP to search for orthographic changes or errors (depending on the corpus), for instance one can study the development of the word-initial h in Spanish by searching for all words that used to be written with an h but no longer are.