This is a “simple” table with the stated goal of hitting a monster with 86% of Physical-based attacks (karma not included). This chart is referencing step deviation table here. Which calculate average - 1 SD. Then the step for that is placed in the chart. Remember that karma is +4. So if you have a PER of 7 and an attack talent rank of 6, you have an ESV of 13 without karma. 17 with karma. This means you can hit Physical defense 10 >86% of the time. If you blindside, this is equal to an effective +2.