SBF, I agree with you, the idea means that the angels were tested as to their loyalty to god, the last test for the angels according even to the WTS, was at 1914 when Jesus and the angel's on god's side battled Satan and the angels supporting fought a heavenly battled and Satan and his supporters were cast down to earth (pardon the wordage). For the 144,000 their test is on earth, and they have to die loyal to their god, at their human death, and raised as tested and loyal as spirits to heaven. For humans, that test is at the end of the 1,000 year reign of Christ over the earth. Satan is let loose from the abyss and goes forth to test humans on earth, disloyal die forever, and loyal ones are deemed perfect with everlasting on earth. So to be perfect, then means angels, 144,000, humans receive a test where they must prove their loyalty to god. So no change, just that is not presented by the WTS in one place for their members to read. (just reporting, not supporting)
"The Bible points out that those who will be with Christ in the heavens as members of God’s heavenly universal government will reign as kings and priests with him. They will be immortal, incorruptible. (Rev. 20:6; 1 Cor. 15:53, 54) Then there will be no flaw, for God has placed them there because of their proved loyalty and has made them in the image of his Son Jesus Christ. (1 Cor. 15:49; Phil. 3:21) Furthermore, even the angels, who will be slaves of God and of Christ, serving under this government, are also of unquestionable moral integrity and will carry out the orders of the government in completeness and perfection. They will see that the righteous earthly princes serving under the heavenly Kingdom carry out pure righteousness on earth.—Ps. 45:16; Isa. 32:1."