I am looking at Chaos Campaign and the Campaign Operations book and I am confused by the math

A mercenary command has four Introductory Rules ’Mechs, six Standard Rules Inner Sphere ’Mechs and two Standard Rules Clan ’Mechs. The percentages of these units in the Force are computed as follows:

Inner Sphere Standard Rules units = (6 / 12) x 100 x 1.5 = 75 percent

Clan Standard Rules units = (2 / 12) x 100 = 16.67 x 2.2 = 36.67 percent

Added together, the total percentage of units with Standard Rules Inner Sphere/Clan technology is thus 111.67 percent (rounding down to 111 percent). This exceeds 30 percent by 81.67 percent, or eight full 10 percent increments

Where does the 2.2 come from? would it not be 2.0? I also can't figure out the next part with 111% the exceed by 30 and the 81.67

DOCTOR! My brain hurts!