Riffy, you are talking about pre-coning, where the manufacturer sets the coning angle at the expected angle for minimal stresses under normal conditions.
Therefore, at flat pitch on the ground, there is a downwards stress on the head (blades not coning up at all) and at the end of an auto or under heavy load, there is an upwards stress - these heads can't please everybody all the time. Fully articulated are able to sort themselves out.