Question on the evolution of 2-J-3

In the 4th Edition, Mr. K has titled 2-J-3 Plane Line Equivalents which later changed to Visual Equivalents in the 6th. The 2-J-3 expanded considerably from the 3rd edition to the 4th as well. Mr. K was obviously making considerable observations as to the various Delivery Lines as seen ON THE GROUND.

1. Does anyone know why he changed the sections title from Plane Line Equivalents to Visual Equivalents? Each procedure outlined in the section is actually a subsitute for the the "True Geometric Plane Line."

2. In the 4th Mr. K explicitly states . . .

It is practially mandatory to always us - IN BOTH DIRECTIONS - the following combinations fo Procedures and Visual Lines: . . .
-B. The visual "Angle of Approach" Delivery Line (2-N) with Drag Loading (Swinging 10-19-C).

In the Fifth Edition, the reference to Swinging with the Angle of Approach 2-J-3 B was not carried forward. Is there any explanation of why this did not "make the final cut?" Why was his mind changed on this?

Thanks!

B