This morning at Abz I checked in (KLM) with a case that weighed 24 kgs and was offered the choice of removing 1kg from the bag or paying GBP60. When I pointed out that on my outbound flights I had paid for 2 cases and had checked in 1 there was a longish phone call from check-in to someone and I wasn´t charged.
If 1kg overweight is going to cost 60 quid then scales calibration has to be challenged.
That said, the flights were great and the CC really excellent.