I was an Adventist all my youth through college and never heard that nonsense.
While you never heard it being taught, it cannot be said that this heresy is not official SDA dogma of the SDA church.
From OFFICIAL SOURCES, here is their fundamental belief #24
24. Serve Christ in the heavenly sanctuary:
There is a paradise in Heaven, the genuine abode of the Lord, not man. In Christ, Christ serves in our name, while making available to believers the benefits of his penitential sacrifice once offered on the cross. He was inaugurated as our esteemed priest, and his intercession service began when he ascended. He explains among the living who dwell in Christ, keep the commandments of God and the faith of Jesus, and thus are ready to be translated into his eternal kingdom. This judgment justifies God’s justice by saving those who believe in Jesus. The completion of this service to Christ will be a sign of the careful observation of humanity before the second coming.
from
https://adventistguide.com/28-fundamental-beliefs-explained/
Compare 2 Timothy 3:16 below with this, how they view the words of Ellen.
All scripture
is given by inspiration of God, and
is profitable for doctrine, for reproof, for correction, for instruction in righteousness KJV
18. The endowment of prophecy:
One of the gifts of the Holy Spirit is prophecy. This blessing is a hallmark of the surviving church, and it was clear in the Ellen ministry. C. White. As a Messenger of the Lord, his writings are a source of continuous and reliable truth that provides comfort, direction, teaching, and correction in the Church. It also shows that the Bible is the standard to be tested in teaching and teaching.
from
https://adventistguide.com/28-fundamental-beliefs-explained/
Quite clearly, they believe that her words are on the same level as the entire Bible.
Were you sleeping during Sabbath School, or flirting with the boys?

(just kidding)
I am not putting you down in saying this, but for some reason, you seem ignorant of these, and other heresies in the SDA church. I suggest that you go to the site from which I pasted this stuff, and carefully read what the 28 Fundamental beliefs actually say. The cure for ignorance us learning the truth, and I only post so you can see what they actually say.