Originally Posted by
offvoice
No idea (but wouldn’t be surprised): it could be that AF/DL pay an extra fee to the handling company for heavy bags, hence why they are less incline to providing some leeway. They are usually ok 23 to 23.9KG (in my experience with AF). But poor customer experience indeed, especially for a FF
it's probably more linked to health and safety rules: a luggage of 23 kg is ok for one baggage handler, but above it it needs to be tagged as heavy and handled by two, leading to more costs for the airline.