Zechirous

Why in the Roedelheim are there only 4 "zechirous" and in other sidurim 6?

Meir

The Magein Avraham (60:2) mentions 4 z'chiros, as did Rav Chaim Vital (Pri Eitz Chayim, Sha'ar Krias Sh'ma, 3) quoting the Arizal.
The Sefer Chareidim (author of Y'did Nefesh) added another 2.
The Chida and Rav Yaakov Emden enumerate 10 z'chiros. In the Siddur Ma'adanei Asher by Weinreb Publishing 5753, all the 10 are listed.

MPerlman