This summary is not the rule. The rule text controls.
If someone sues you and you file a counterclaim against them, your counterclaim does not have to match or cancel out what they are asking for. You can ask for more money than they are seeking, or you can ask for something completely different from what they want.
This means the two claims in a lawsuit do not need to balance each other out. For example, if someone sues you for $5,000, you could file a counterclaim asking for $50,000, or you could ask for a different type of relief entirely, like having a contract cancelled instead of getting money. The court will look at both claims on their own merits, regardless of how they compare in size or type.
This rule gives people more freedom to bring up related problems in the same lawsuit, instead of forcing them to file a separate case just because their claim looks different from what the other side is asking for.