Total skill factor is combination of theory and practice factors of the skill.
Example: You have level 4 theory and 71 practice on wrestling skill, it gives total 1.75 x 1.80 where 1.75 is Sage level theory, and 1.80 is Taskamaster practice of the wrestling, so total wrestling factor is 1.75 x 1.80 = 3.15
Maximum skill factor is 3.50 x 3.50 = 12.25 where both theory and practice are maximum 6 and 100.
Example 2: When we calculate player dodge chance, the formula is: (1.05 * wrestling total factor) + agility + agility bonus + blockade perk points * 2 + (wrestling total factor * 1.2) + (avoiding total factor) and (if defensive stance is on then + 1.05 * stancing total factor.