[Avodah] Three steps back

[Moshe Y. Gluck]

The Beis Yosef (OC 123) says that one of the reasons we take three steps
back after Shemoneh Esrei is because at Matan Torah the Yidden went back
three Milin - our three steps parallel that. The problem is that all the
Midrashim I could find said that the B'nei Yisrael went back 12 Milin! Rashi
on the Pasuk (Shemos 20:14) also quotes this, so it was no secret. I could
not find any other measurement for this. The only solutions I could think of
are either that there is another Maamar Chazal somewhere that says three
Mil, or that there is a typo, and it should say three _Parsaos_ (which equal
12 Mil). If the latter Pshat is correct, one must wonder how all the
Rishonim and Acharonim quote this Pshat without the correction. Of course,
that's what leads me to conclude that the Pshat is incorrect, which further
leads me to ask again, where is the source for the B'nei Yisrael moving back
three Mil by Matan Torah?

KT,
MYG