OK, lots of questions, guys. First let me say that in all the years I've been flying this route I never had to pay extra baggage charges for my feeder LH flight when connecting to a flight to or via the US to Australia (I normally fly TXL-FRA-LAX-SYD on LH and UA without stop in the US). I could maybe understand this if the two flights weren't on the same ticket but in this case they were, of course.

I also think it's irrelevant whether there was a 24h stop in the US or not. The fact that the flight went via the US is covered in the LH baggage rules as qualifying for the piece concept. It specifically says "via the US" and interesting, it doesn't say "via" when it talks to flights to Canada, so problaby ruling this one out. I wasn't even aware of this.

I still believe LH that the ticket was issued incorrectly. And to be honest I had one LH agent in Sydney once ticket my C class ticket to Germany via the US with only 30kg. It was a mistake and she rang me up prior to the flight to let me know that she made an error and asked whether she should fix it. But me being *Gold I didn't need more than 50kg anyway on that trip, so it was fine. But basically, yes, these kind of things can happen if the agent issuing the ticket didn't do it carfully. So, all I'm saying is that I'm not willing to pay for a mistake BD has done especially after mentioning the reason for this routing was the extra baggage via the US and the guy first had to check with his supervisor that the flight indeed went via the US.

How complicated do airlines want to make it when it comes to baggage allowances now? You need a PhD to work out what weight applies to your flight by now...mind you, even this didn't help me

UPDATE: Just rang LH again to confirm that all feeder flights on LH should also get the piece concept if you are connecting to a flight to/from/via the US. So, that confirms what I always experienced. And I asked the lady about stopping in the US and this is not required. As long as your flight goes via the US the piece concept should apply to all segments on the same ticket. So, the ticket must have been issued wrong.