holo said:
They hold EGWs writings to be equal to the bible (this is official SDA doctrine if I'm not mistaken)
You are mistaken.
1. The Holy Scriptures:
The Holy Scriptures, Old and New Testaments, are the written Word of God, given by divine inspiration through holy men of God who spoke and wrote as they were moved by the Holy Spirit. In this Word, God has committed to man the knowledge necessary for salvation. The Holy Scriptures are the infallible revelation of His will. They are the standard of character, the test of experience, the authoritative revealer of doctrines, and the trustworthy record of God's acts in history. (2 Peter 1:20, 21; 2 Tim. 3:16, 17; Ps. 119:105; Prov. 30:5, 6; Isa. 8:20; John 17:17; 1 Thess. 2:13; Heb. 4:12.)
18. The Gift of Prophecy:
One of the gifts of the Holy Spirit is prophecy. This gift is an identifying mark of the remnant church and was manifested in the ministry of Ellen. G. White . As the Lord's messenger, her writings are a continuing and authoritative source of truth which provide for the church comfort, guidance, instruction, and correction.
They also make clear that the Bible is the standard by which all teaching and experience must be tested. (Joel 2:28, 29; Acts 2:14-21; Heb. 1:1-3; Rev. 12:17; 19:10.)
http://www.adventist.org/beliefs/fundamental/index.html
Seventh-day Adventists hold the Protestant position that the Bible and the Bible only is the sole rule of faith and practice for Christians. We believe that all theological beliefs must be measured by the living Word, judged by its truth, and whatsoever is unable to pass this test, or is found to be out of harmony with its message, is to be rejected.
True Christianity receives the word of God as the great treasure house of inspired truth and the test of all inspiration.—
The Great Controversy, p. 193.
We are to receive God's word as supreme authority.—
Testimonies, vol. 6, p. 402.
In our time there is a wide departure from their [the Scriptures'] doctrines and precepts, and there is need of a return to the great Protestant principle—the Bible, and the Bible only, as the rule of faith and duty.—
The Great Controversy, pp. 204, 205.
http://www.sdanet.org/atissue/books/qod/q02.htm