I noticed that the inclusion of the word "b'rachamav" doesn't seem to be consistent. In the Artscroll siddur I have handy, the word appears at the end of the Kaddish derabonon in pesukei dezimrah but not the Kaddish yatom which follows it, but in the kaddish yatom after aleinu for weekdays -- absent from the kaddish yatom after aleinu on Shabbat.
In my Siddur Tefillah Hashalem (Greenwald), the word is not in the kaddish yatom before baruch she'amar on weekdays but IS in the kaddish yatom before baruch she'amar on Shabbat (and in the kaddish yatom after aleinu on weekdays).
Are there rules about where the word is included based on the day of the week or the location of that kaddish in davening, or is this a matter of inconsistent editing?
[note -- I have found what I think is another example of inconsistent girsa'ot between 2 siddurim from the same publishing company but not within a single siddur]