This summary is not the rule. The rule text controls.
If you're filing a lawsuit against someone who runs a business office in a different parish from where they normally live or would otherwise be sued, you have another option for where to file your case. You can bring the lawsuit in the parish where that business office is located, as long as the matter you're suing about was actually handled or overseen by that specific office.
This rule gives you more flexibility when a person or company has a business presence in one place but their legal home (for lawsuit purposes) is somewhere else. Instead of being forced to travel to file where they'd normally be sued, you can file where the business office that dealt with your issue is actually located. This only works if the office had real supervision or control over the matter you're suing about, not just any minor connection to it.
This matters because it can save you time and make the process easier if the business dealings happened far from where the person or company is normally sued. It puts the lawsuit closer to where the actual business activity took place.