I'm curious as to why they didn't cover it under the service bulletin. Because yours didn't throw up a lamp error?

My official answer is that a service bulletin is something issued to the dealers to fix the problem properly. As in they acknowledge that people are having this problem so they've found an appropriate fix to it. But because it's not hazardous or happening to enough people, they're not recalling it and are only repairing it under bumper to bumper.

Correct. A SB is simply official instructions to fix a defect IF IT IS FOUND.

Your warranty covers defect. Unless you discover the defect when the car is under the warranty, you are SOL. Irrespective of BMW having an official repair procedure, if the defect occurs outside of the warranty it is not covered.

A 'recall' is entirely different, it is when safety is involved and a repair is needed to avoid a safety issue.