Great news, I am glad they're making good on that. Something you said sparked a curiosity for me though...

Is FE deterioration a common precursor to the battery problem? I have been experiencing a progressive drop in mileage. It started when I got new tires, but it stabilized after that and now it still seems to be going down a year later. My last tank was 37. A year ago I'd never had one below 40, nowadays I can't seem to get one above 40. It's at about 80k mi.