I read the other thread and then I found the rules online here:
https://the-black-hack.jehaisleprintemps.net/ (says it's used with permission... who knows!)
My opinion without testing or playing it:
It's a fuckload of shite if it's pretending to be OSR. It is not OSR. According to the armor rules, this rule has no variable absorbtions, being between 2 to 8 points: "Armor provides protection by reducing all incoming damage. Each type will reduce damage by a limited amount. Armor Points are regained after a character rests. Once the player or monster has used armor to absorb its maximum amount, they are too tired or wounded to make effective use of it again - they then begin taking full damage."
In addition to this, the "Monsters don’t make tests - a character must avoid their attacks by making a test, the only time a monster would roll is for damage." makes little sense to me. WHY not have the DM roll the monster's To Hit, and THEN figure out IF the PC avoided part of the blow, and if not, then spend armor points to see if -xd4 is removed from the damage given. Actually, I don't like the idea of calling it armor points - should be FATIGUE POINTS if going that route - have the player decide if HP loss or temporary sagging stats would be better - give both GM & players agency! *sigh* But that's just my opinion...