Ceiling joists may not carry construction or worker loads until fixed and restrained by linings or battens, and battens never; battens suit the ceiling mass; ceiling joists match rafter spacing and direction in coupled roofs, acting as ties at the rafter feet, in single lengths or spliced; they hang from hanging beams by cleats, straps or hangers on alternate sides; ceiling openings are trimmed by size band (openings over 3000 mm trimmed as hanging beams); and ceiling joists carry ceiling loads only, with platforms for water heaters or tanks designed for them.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.