I really Enjoyed researching this topic because you may already know < I like to Look into multiple Texts or the Torah. Samaritan text is different than the Septuagint and the Masoretic is different than Josephus that's for sure. But did you know that One of the Four actually agrees with the New Testament Book of Acts of the Apostles. IN Acts chapter 7 we find out that Abraham Leaves Haran After his Father Dies of old age, But Acts never tells us how old Terah was.
The text that seems to agree with Acts at least for this one occasion is the Samaritan Text. The Samaritan Text is another Hebrew Document however there are quite a few differences between it and the Masoretic Text. anyways we see that Terah Dies at the age of 145 and not 205 like the rest of the texts state.
Is it really important to know the Dates and times the people were alive when they were born and died? many people would seem to think that it didn't matter, BUT i think it Does . the reason i think it does is that it can help deduct which text may have come about first. So far all i can see is that basically all the texts have piggy backed each other.
I think the reason that the Samaritan text says that Terah Died at the age of 145 is because Abraham would have been 75 at that time and they wanted to correct or mend a potential inconsistency in the text. It worked if its only purpose was to agree with Acts. But other than that there was no reason for the Samaritan text to disagree with the other texts.
Masoretic Genesis 11-12
Septuagint Genesis 12
Josephus 6:151-7:1 Samaritan Genesis 12