How do you accurately estimate the painting expenses for a Home Office in Lugano with excluding ceilings, 2 doors, and 2 windows, covering an area of 4m x 8m?

Accurately estimating the painting expenses for a Home Office in Lugano with excluding ceilings, 2 doors, and 2 windows, covering an area of 4m x 8m, has a price tag of CHF 282.00.

*) The calculations are approximate, based on a room height of 2.4m, and include one coat of paint. The price covers only the labor, excluding any services or materials.