It's also an unwise conclusion that "the bright morning light that grows brighter and brighter until full daylight" has even the slightest bearing in our day on whether Watchtower teachings evolve in one way or the other.
A basic Christian teaching is that doctrine is "fixed" by the apostles. It cannot morph and certainly cannot flip-flop once presented by the apostles.
Paul wrote the below words to address this very issue, after seeing how some folks were easily fooled by those that would change the gospel.
Galatians 1 - I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel:
7 Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.
8 But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
9 As we said before, so say I now again, if any man preach any other gospel unto you than that ye have received, let him be accursed.