There is a fine line when one looks at "the church" and its mission. Look, for example at baptism. Baptism is an act that brings a person into "the church." If a person wanted to be baptized into Christ but not into a congregation, would the Adventist denomination allow for that? Is the intent to bring people into support of the structure, or is it to bring them into a relationship with Jesus?
That said, despite the structural complexity and obvious top-heaviness of the SDA denomination, it remains that individual congregations and conferences often have a surprising autonomy. I live in a conference that ordains women as pastors despite the General Conference which disallows it. The Church Manual says that there is no higher authority under God among SDAs than that of the General Conference in session. But although the GC in session has consistently voted down the ordination of women, we have long been ordaining women as pastors here. They baptize, preach, teach, counsel and do everything that their male counterparts do, for pay, and the GC does not interfere. It has been argued that this is because our conference brings in more money for the world church than most divisions, yet the fact remains that we, and other conferences, have shown substantial autonomy.