Optional Recommendation Letters?

Hello CC,
On my Common App I know that the colleges that I am applying to all have an optional recommendation letter that I could give to them. Should i necessarily turn in another optional recommendation letter or not? I heard a rumor that colleges only read the required number of recommendation letters and they randomly pick a recommendation letter that was sent. I have also heard that the optional is used to make decision if the first one they read is kind of weak and not that insightful. So how important is this optional recommendation letter?
Thank you

If the college accepts add’l recs, and the additional rec adds something unique that is not covered in the other recs, send it. If it is more of the same, don’t.

Unless you were personally told something from an admissions officer, don’t rely on things you have heard, particularly if it’s from other HS students who don’t know how much they don’t know.