[Yoda]

...Single Wrist Action will naturally bring your Elbow to a Punch position, while Standard Wrist Action will naturally bring it to a Pitch position.

Yes, and this is one of the very few times I would recommend usng a given photo to reference a component other than that being illustrated (2-R).

Compare the Elbow postion in Photo 10-18-A (Standard Wrist Action) and the Elbow Position in 10-18-C (Single Wrist Action). [IMPORTANT: You must use Photo 10-18-D for 10-18-C because the photos are transposed.] The Turned Left Wrist of Standard Action has enabled the Elbow to 'lead' deeper into Release Interval (Pitch Basic Stroke) than the Vertical Left Wrist of Single Wrist Action (Punch Basic Stroke).

The untrained eye may not at first be able to detect an appreciable difference betweeen the two. But it is there. To help see it, check out the space between the Forearms in the Single Wrist Action photo as the Right Forearm supports the back-of-the-Shaft Loading (instead of Standard Wrist Action's top-of-the-Shaft Loading.