How do you make a precise estimation of painting expenses for a Bedroom in Winterthur with excluding ceilings, 1 doors, and 2 windows, covering an area of 3m x 10m?

Making a precise estimation of painting expenses for a Bedroom in Winterthur, excluding ceilings, 1 doors, and 2 windows, covering an area of 3m x 10m, involves accurately calculating CHF 397.00.

*) 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.