Haha, sure....good question.......yep I can explain.....they are the cumulative points of spread (or range) for each wave (in some respect, the wave chart is sort of like a modernised Point and Figure chart).
In a nutshell.....Buying and selling usually occurs in waves.
On a 'normal' wave chart, the cumulative volume numbers for each wave are shown (which are just the volume for each bar in the wave added together, until each individual wave is complete), and these volume numbers are used as a way to illustrate the strength of the waves of buying and selling. And the wave numbers can then be compared to each other (along with their length and duration), to gain some understanding of the strength or weakness of the buyers and sellers in the market at that time.
Under most (but not all) circumstances, volume and spread are a good proxy for each other, so on that chart I have replaced the 'normal' cumulative volume numbers, with cumulative points of spread (or range) for each wave.
It is experimental up to a point, one I have run for quite some time now, and seems to work OK.
(20min delay)