[Avodah] Psukim tacked on to Shir ha-Ma'alot

[Achdut18]

At the end of Shir ha-Ma'alot, some have the minhag of adding several p'sukim,
beginning with "t'hillat ha-shem y'daber pi."

What is the origin of this?

One rabbinic scholar told me that it was chassidish, going back to
the last quarter of the 18th century, reflecting chassidic tendencies
to personalize prayer and create a more initimate connection to G-d.

Another scholar has suggested that it may have been a desire to tone
the Zionist theme of Shir ha-Ma'alot.

Are there any sources that discuss this?

//Avi

Avram Sacks
Skokie, IL