Is it any possible that the 4-dot-ellipsis is just the combination of the 3-dot-ellipsis and a period? however, in this case, I think that there should be a space between the 3 dots and the one dot - "... .".
In general, as far as I have observed people put ellipsis when they omit words, phrases or a sentence for the text they quote from. Also, I did some online research and according to the information I found ellipsis is also used to indicate a pause in speech, an unfinished thought, or, at the end of a sentence when the intent is silence. Additionally, when placed at the beginning of a sentence, the ellipsis can inspire a melancholic tone.
Also, MLA requires to have spaces between the dots of the 3-dot-ellipsis - ". . . ", whereas APA does not -
All in all, ellipsis usage still strikes as tricky for me.