How do you perform an accurate calculation of painting costs for a Home Office in Lausanne, including ceilings, 1 doors, and 1 windows, with dimensions of 10m x 4m?

Performing an accurate calculation of painting costs for a Home Office in Lausanne, including ceilings, 1 doors, and 1 windows, with dimensions of 10m x 4m, consider paying CHF 824.00.

*) 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.