If each level of the mind, the conscious, the upper subconscious, and the deep subconscious, can hold beliefs independently, does this help explain why oftentimes people act in a way contrary to what they think they believe; for example, treating people harshly or making an intemperate remark?

This happens all the time, especially when people act more through emotion than reason. What is happening when people say, “I lost my head,” after a rash act, is accurately describing that for a moment, their conscious higher executive self was shoved aside and the subconscious of the inner child was in charge and the person was acting through emotion and not reason. Everyone experiences this and witnesses it again and again in others, and this is a very common explanation for erratic behavior or a perceived difficulty in maintaining a steadfast performance without excesses, or gaps in quality and consistency.