The copy I have is a 1969 version with a red cover, and the graph is exactly as you describe. Depending on which version you have they either show the pilot and passenger as 170lbs each, or 200lbs each including parachute.
The slopes in the graph just show the C of G change as the fuel burns with one person [200lbs] or two people [2 x 200lbs]. The assumption is that the pilot and passenger both weigh 200lbs as per the example in the table.
If you look at the graph the far left of the graph for two crew [i.e. full fuel] this equates to the calculation shown in the table. In the graph for the 22 and 22A this shows it right on aft limits with all useable fuel burnt. The slope equates to the arms as shown in the table.
Hope this helps. Feel free to PM me if you have any further questions.
