Not sure I understanding what your saying. Are you talking about dividing the last range from low to high and projecting those divisions into the future?

I was basing this discussion off the following few lines from Chapter 5 1951 version "The Basis of My Forecasting Method for Grains-Geometrical Angles" under the paragraph titled..."Latitude and Longitude". As is the case with a lot of his works the wording is somewhat jumbled. From the paragraph title we see he is discussing latitude and longitude and placing horizontal and vertical angles on at the critical divisions of the circle...11.25, 22.5, 33.75, 45, 67.5 78.75, 90, 101.25, 112.5, 120,.

Gann:

“On all charts-daily, weekly, or monthly-the price must move up or down on the vertical angles. Therefore, the price movement is the same as latitude.
You should begin with 0 on any chart-daily, weekly, or monthly- and draw the important angles and resistance levels across which measures latitude.

Next, number the time points in days, weeks, or months across and draw the horizontal angle at each natural angle, such as 11.25, 22.5, 33.75, 45, 67.5
78.75, 90, 101.25, 112.5, 120, etc. Then you will know when price reaches these important angles and meets resistance.

Longitude measures the time running across the chart, as it moves over each day, week, or month. Therefore, you must keep your chart numbered from each
important top and bottom in order to get the time measurements, according to angles. These important angles, such as, 11.25, 22.5, 33.75, 45, 56.25, 50, 78.75,
90, etc. from each bottom and top will show you where the strongest resistance in price and time takes place. These angles prove the parallel or crossing point.
Study past records and see what happened when prices on monthly charts reached these important angles or time periods.”