For my understanding of this tables:
It is used some kind of distance from arc:"Calculated by using minimum approach from Table 441-2 and subtracting two times the assumed arc gap length"
Does this mean that for instance the 161 to 169 kV calculation is done wirth the following input:
Ik= 20kA(assumed single phase)
Arc Gap distance 161kV/10=16.1 inch
Distance to gap: (From table 441-2): 51 inches(10ft3inch,use T=3)-2*16.1 inches=19 inches
If I do calculation with arcpro(is was told that this tables where made by using arcpro?), input shown in picture. I get a result of 11.9 cal/cm2 and not 4cal

The table uses line to line voltage, but when finding arc length the note 1 says to divide the line to ground kV by 10. Your calculated arc gap should be divided by sqrt(3).

When I've looked at this in the past, I found the tables did not necessarily correspond to the MADs in the same revision of the NESC. Looking back a revision or two produced better results.

Why 9.3 cycles? Tabulated value is 11.9.

Might try changing the electrodes; I forget which gave better results.