The product catalogue and spread rates
Every material category has a selected product — a specific paint from a specific brand — and your cost per L for it. Choosing a product fills in its cost; a cost you type yourself always wins.
Choosing a product
Open a material category in Materials and tap its product. You'll see the top manufacturers serving your region. The prices shown there are starting points — your supplier invoice is what matters.
Spread rate
Each paint has a spread rate in m²/L — how far one L goes. Leave it on Depends on the surface and every surface goes at its own rate; the Materials screen lists what those rates are. Or pick one of eight steps, from Soaks it up to Covers well, and every surface painted with it starts there. You can still change any one surface while measuring.
Products you add yourself
Use something the list doesn't have? Add it in Materials — the brand, the product name, and your cost for each sheen you buy it in. Pick it on a surface and that surface is priced at the cost of its sheen.
Spray vs brush/roll
Choosing spray as the application method on a surface leaves the spread rate exactly where it was. Spraying does lose paint to overspray, so the step one below the surface's default is marked Typical with overspray — pick it if that's what you get. There's no hidden multiplier; the rate you see is the rate it uses.
Why it matters: paint overruns eat margin silently. A 10% variance between quoted and actual paint usage can destroy the profit on a medium repaint. Setting the spread rate you actually get, and the price you actually pay, keeps the paint line on every quote honest.