Something for newcomers, since it's not a custom home rule at all.
As I was summarizing the Combat Resolution Table in Excel, I think one can write it more simply. It confused me for a while and, hopefully, I can help other people be less confused?
In addition to the table below, Fumbles roll on the Fumble tables and Dodge avoid the parry effects.
(Why parry then? Somethings can only be parried, that's why! Plus, parries might have additional benefits, like a riposte)
Also, omitted from the table for brevity: Same level of success => nothing happens!
Attack Roll
Defense Roll
Resolution
Crit
Fail
(Max Weapon Damage OR Special), Armor Ignored
Crit
Success
Special, parry weapon takes 4 damage
Special
Fail
Special
Crit
Special
Normal damage, parry weapon takes 2 dmg
Special
Success
Normal damage, parry weapon takes 2 dmg
Success
Fail
Normal damage
Success
Special
parry: attacker's weapon takes 1 damage
Special
Crit
parry: attacker's weapon takes 1 damage
Success
Crit
parry: attacker's weapon takes 2 damage