Take it easy.
Henzell says...
  1. Adjusted body armour evasion penalty. Affects spell success, melee and missile accuracy. Its value is [(2/5) * er^2 / (str+3)] * [45 - armour_skill]/45.
  2. Calculator: 'https://docs.google.com/spreadsheets/d/1SgY-b12lecR1EHb7uopTqFP0E3FDr5_MsTHrwA0Z5MY/'

Information based on master branch and the great LearnDB.
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