Your Cross section example for the geoid/ellipsoid/ground is "wrong". Not wrong but at least confusing in the way it's shown. In your representation, N would be a negative value, so "H-N" would be equal to adding absolute H and N. At times the geoid is "above" the ellipsoid and it's easier in that representation to visualize H-N.
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Your Cross section example for the geoid/ellipsoid/ground is "wrong". Not wrong but at least confusing in the way it's shown. In your representation, N would be a negative value, so "H-N" would be equal to adding absolute H and N. At times the geoid is "above" the ellipsoid and it's easier in that representation to visualize H-N.