Every sheet is scanned to detect the drawn runs — the colored linework — and each run is measured by how much drawing ink it covers. When you mark a run, it earns its legend color's percentage of that ink: "50% Done" earns half, "100% Done" earns all of it, and a color with no percentage (like Note / Issue) earns nothing. Sheet % = earned ink ÷ total detected ink on the sheet. Job % is the same math across every parsed sheet. It tracks field progress against the drawings — a good proxy for installed footage, not your estimate takeoff.