Two magnesium oxysulfate cleanroom panels can look identical on a quotation sheet yet quote 30–120% apart once raw material purity, anti-efflorescence additives, core density, face gauge, edge sealing, and coating system are unpacked. The spread is rarely pure margin: it hides in the sulfate-to-oxide ratio, halogen content, curing protocol, reinforcement mesh, and composite lamination method. This module disassembles the cost stack for overseas procurement engineers, cleanroom GCs, food & beverage EPCs, and tropical/coastal project buyers, then reassembles it into a manufacturing workflow for audit-grade magnesium oxysulfate cleanroom panel. SAMZOON, a Foshan source manufacturer, anchors the walkthrough with free pre-bid coupons, custom thickness, and South China wet-environment project QC.