The instructions on installing the the USB chargers weren't clear to me, and it wasn't until I saw an S install at the dealership that I realized I'd missed a step. Attached is a pic showing a part in my hand that slides off to the left (toward the driver). This part must be removed to install the USB cables correctly. The install was super easy, but getting the courage to figure out how this piece came off was gut-wrenching. I hope this spares others from the same anxiety.