The "chassis value" function (there's no mark suggesting what name Illwinter may have given it) is used in a variety of places, out of a lack of other solutions I thought it sensible to put it here.

• Calculate "HP value": (current HP + 10)/2, rounded down
• Score is the following things added together:
  • ((attskill - 10) * HP val)/10
  • ((defskill - 10) * HP val)/10
  • HP val
  • ((prot - 7) * HP val)/30
• If prot is 14+:
  • score = ((prot - 3) * score * 10)/100
• If unit is ethereal, double score
• If the unit is regenerating, score = ((regen % * 3 + 100) * score) /100
• Add fear value to the score, if any
• If the unit has fire shield, add (HP val/3)
• If the unit has awe, add (HP val/3)
• If the unit has either heat or chill aura, or both, add (HP val/3)
• If the unit's base chassis is a trampler (not via items), add (HP val/3)
• If the unit's base chassis is sacred (not blessed via items, pretender, prophetising etc), add HP val
• If the unit's base chassis has 13+ morale, add 20% of hpval to the score
• If the unit's base chassis has 9 or lower morale, subtract 20% of hpval from the score
• For each weapon on the unit:
  • If this is the unit's first weapon:
    • If the weapon's length (without size modification) is 0 or 1, subtract 10% from score
    • If the weapon's length without size modification is 4-6, add 10% to score
  • Otherwise
    • If length without size mod is 0 or 1, add 20% to score
    • If length without size mod is 2 or 3, add 25% to score
    • If length without size mod is 4-6, add 30% to score
• Chassis value can't be smaller than 5

Alternatively, here's one I made earlier