Exactly. It does not say they added to Scrioture what was not there to make sence of it BUT that they understood the reading.JonC simply rejects neh. 8
8 So they read in the book in the law of God distinctly, and gave the sense, and caused them to understand the reading.
and Lk24;
25 Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken:
26 Ought not Christ to have suffered these things, and to enter into his glory?
27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.
What you do is reject Scripture (the text) in favor of theorizing about Scripture. That is the wrong approach.
How can you test the theory that Chrust died instead of us? You can't with Scripture.
What you are doing, unintentionally I'm sure, is the same that the Jewish leaders did in Christ's time. You are using Scripture to support your understanding rather than relying on Scripture to derive an understanding.