How do you perform an accurate calculation of painting expenses for a Living Room in Biel, including ceilings, 2 doors, and 1 windows, with dimensions of 6m x 10m?

Performing an accurate calculation of painting expenses for a Living Room in Biel, including ceilings, 2 doors, and 1 windows, with dimensions of 6m x 10m, consider costing you CHF 760.00.

*) 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.