It is very possible that when Origen edited the LXX, that he tried to make it conform more to the New Testament.

It appears to me as if the Septuagint was made in 275 B.C. The translations of Aquila, Theodotion and Symmachus were made after the time of Christ. Then they were all brought together in the Hexapla.

The reason why the New Testament quotations are not exactly the same as the LXX is because the Holy Ghost was giving His translation of the Hebrew in Greek. That means that when the penmen used the LXX, they were in fact being directed by the Spirit under inspiration.
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