Sitting in a house facing south, why is the foundation of the East House lower than that of the Westinghouse?

In China's traditional geomantic omen, you sit in a house facing south, with Qinglong in the east and white tiger in the west. Qinglong represents the East in China culture, and also represents a dynamic and upward force, so the position of Qinglong should be high and appropriate. In China culture, the white tiger represents the West and also represents a calm and stable force, so the white tiger should keep a low profile and be quiet. This is because in Feng Shui, the white tiger can't be taller than the green dragon, otherwise it will be bad for the male host at home and affect the career and fortune. Therefore, in order to follow the principle of geomantic omen, the foundation of the East House is usually lower than that of the Westinghouse.