Tikun Soferim or Kinah Hakatuv?

There is a very interesting discussion on understanding the pasukim listed as 'corrections' made ​​by the soferim. The expression tikun soferim is first found in a statement of Rabbi Yehoshua ben Levi in the Midrash to explain the reading on Zechariah 2:12 :

According to R. Yehoshua ben Levi, the correction of the soferim modified only a single letter in order to avoid disrespect to Hashem.

A well-known view mentioned is Rashi on Parashat Va'yera:

Does Rashi assumes that Tikun Soferim is a real correction made by the soferim?

Here's his source:

The correction of the Soferim according to Rabbi Joshua ben Levi was limited to one letter only. But his pupil, Rabbi Simeon, contended that in one place the Soferim inverted the order of the subjects in the verse. We do not know whether Rabbi Simeon's statement was based on a tradition or whether he derived it from the context. I think his statement fits on daat yachid, at least it would explain a lot of our queries.

It seems more likely since the Talmud does not refer at all to the concept of tikun soferim, but "a statement in Yerushalmi, Bikkurim 3:3 can be better understood based on the concept of Tikun Soferim and the words of Rabbi Shimon. The Talmud states in the name of Rabbi Shimon that Hashem said He was the first to stand up for a Zaken. Since the Talmud Yerushalmi offers no source for this claim, it makes sense to say that Rabbi Simon mentioned his own drash earlier that Hashem was standing (omed) while waiting for Avraham" (A. Lieberman).


Tikun soferim in Midrash Halakha

In Mekhilta of Rabbi Ishmael, (Beshalach, parasha VI) the same pasukim mentioned in Midrash as tikun soferim are referred there: However, when Mekhilta mention them they are not identified as Tikun Soferim but as כנה הכתוב - the verse itself (and not the soferim) has recorded the text in a euphemistic/literary form, therefore no correction actually happen.

Thus, there are two concepts in our sources: The expression תיקון סופרים which indicates that the original text was corrected and כנה הכתוב which denotes that it was originally written this way to avoid a disrespectful language. The first case (tikun soferim) is found in Midrashim and Aggadeta and the the second one (Kinah Hakatuv) is found in Midrash Halakha (Sifri, Mekhilta). Apparently תיקון סופרים is just another way of saying כנה הכתוב in an euphemistic way already present in the original text.

In another commentary of Rashi, something rather curious, these two concepts are used as if they were synonyms:

Many sources in the Midrash Halakha use the terminology, "the Scripture used a substitute expression", "this is an euphemistic expression", "and the Scripture modifies the expression"(which is the case of Mekhilta and Sifri). It seems (and this opinion fits in sources based on Midrash Halakha) that tikun soferim is a development of kinah hakatuv. The Rashba for example, when discuss the subject he teaches that tikun Soferim is actually kinah hakatuv:

שתקנו אותן, שמחקו וכתבו אלא מה שכתב משה רבינו ע”ה בתורה ומה שכתבו הנביאים בשאר ספרים מתחלה מה שכתבהו על כנוי כתבהו, והספרים לא חסרו ולא יתרו רק ראוויין להקרות בכנוי כתבן .