Injector Status

[Preggie Naidoo]

Hi guys, my 335i, N54 engine had the injectors replaced by BMW in 2011 under a general campaign. No idea of the index and BMW dealership needs to physically r amine the injector to verify. Question is, should I upgrade to index 12 if there are no issues, but do so as preventative maintenance?
Regularly use BMW fuel cleaner additive which I understand is Techron concentrate and is supposed to assist in keeping injectors clean.