This new line may not readily come to be accepted by those who have lived with the original eight lines provided by Tatsuo Sensei or those who received their version from reference to the Bubushi. This would be a normal reaction and in time it is hoped that the last new line would become apparent in the first eight and make sense showing its importance in making a full connection the the three that make the one.
It becomes very easy to miss this important aspect of training and practice in the jutsu and do of any martial art. The senses of sight and hearing are primary to all humans. Even the touch sense dominant person switches between those two. It becomes critical for the tactual person when stress and its chemical effects kick in for the human being uses the dominant sense much like the freeze and the flight or fight response of survival. Look at it like the adrenaline dump experienced in a threat stress induced situation. There are particular aspects that take over like narrowing of vision and dysfunctional perceptions all to provide survival instincts.
Look at it as a way to see the view from this perspective, to hear the value of it for all the senses and to grasp it firmly in our hands and minds to provide a triangle of completeness - sight + hearing + tactual/tactile/kinesthetic.