A Succah Higher Than 20 Amot

The beginning of masechet (2a) Succah discusses the law that a succah cannot be higher that 20 amot. Different reasons for this law are given. The first, given by Rabbah, is that the verse in Vayikra 23:42 states that the reason for sitting in the Succah is לְמַעַן יֵדְעוּ דֹרֹתֵיכֶם כִּי בַסֻּכּוֹת הוֹשַׁבְתִּי אֶת-בְּנֵי יִשְׂרָאֵל,, "that your generations may know that I made the children of Israel to dwell in booths." Until 20 amot, a person knows he is dwelling in the Succah. (When the schach is) Higher that 20 amot, a person does not know that he dwells in a Succah, because his eyes do not reach that high. In Hebrew/Aramaic:
"Ad Esrim Ama, Adam Yodea SheDar BaSuccah; Limaala MeEsrim Ama, Ein Adam Yodea SheDar BaSuccah, Mishum Delo Shalta Bah Eina." (From Mishum until Eina is Aramaic, before that is Hebrew.)

The specific word "Dar" (dwell) seems out of place. "Yoshev" (=sit, dwell) seems more appropriate, given that that the pasuk states כִּי בַסֻּכּוֹת הוֹשַׁבְתִּי אֶת-בְּנֵי יִשְׂרָאֵל. At first glance, the derasha seems to be either on the word Yedu (know), namely that the person sitting in the succah must know he is doing so. Or, we might say, the entire purpose of sitting in the Succah is to know that Hashem caused our ancestors to dwell in Succahs in the midbar. Unless we know we are sitting in a succah, we can't then realize the reason for sitting on a Succah. Both of these are hard. Lets examine Rashi.

Rashi writes, "לְמַעַן יֵדְעוּ: Create a succah such that the sitting in it (yeshivata) is evident to you, as it says לְמַעַן יֵדְעוּ כִּי בַסֻּכּוֹת הוֹשַׁבְתִּי. (Rashi takes out the word דֹרֹתֵיכֶם and אֶת-בְּנֵי יִשְׂרָאֵל, thus stressing that you should recognize that YOU [NOT the Jews in the midbar] were made to sit in the succah. He then explains what Hoshavti means:) I commanded that you dwell. So did they darshen it. And even though [the verse] does not leave its pshat that the Clouds of Glory surrounded them, however, they darshened it for a derasha."

My own suggestion as to what the derasha is is based on the curious word Dar. If, like Rashi, Hoshavti is a key word, why switch in the explanation to the word Dar, which means the same thing but lacks the echo of הוֹשַׁבְתִּי?

I suggest it is an Al Tikra. Don't vowelize a word to be X but rather to be Y. (This is on the level of drash, not pshat in terms of establishing a girsa in Tanach.) Dont read דֹרֹתֵיכֶם, Doroseichem, your generations, but דִירֹתֵיכֶם, Diroseichem, your dwellings. The pasuk would then read לְמַעַן יֵדְעוּ דִירֹתֵיכֶם, that you should know your dwellings. Until 20 amot, a person knows (Yodea) that he dwells (Dar) in a Succah, but more that 20 amot he does not know (yodea) that he dwells (Dar) in a Succah.