I'm not sure why they wouldn't cover this issue as it's not your fault this has happened. I would expect them to swap the whole AVCS systems between the banks and see what happens, all should be covered under warranty. ECU changes aren't going to make any difference as @
steve99 pointed out you're already running a calibration that was released for this. We assume that all this did was change tolerances for the code to pop up, it won't correct the hardware issues that cause this.