[KLS]

	if (attacker->IsClient()) {
		int modAA = 100;
		switch (attacker->CastToClient()->GetAA(aaPrecisionofthePathfinder)) {
			case 1:
				modAA += 2;
				break;
			case 2:
				modAA += 4;
				break;
			case 3:
				modAA += 6;
				break;
		}
		chancetohit = ((chancetohit * modAA) / 100);
	}

In regards to the first two it is correct because mod starts at 100. So with rank 3 you would have a mod of 106. Assume you have 50% chance to hit: ((50 * 106) / 100) = 53 chance to hit.