I'm prepared for backlash.
I was charged excess for my hand luggage as it was over a certain weight- that's absolutely fine. The combined total weight for myself and my cabin baggage was approx 69 kg. My friend wasn't charged because their luggage wasn't overweight yet the combined total for them and their luggage was over 90kg. My friend joked about how unfair it was.
Surely it would be fairer to use the combined weigh of traveller and cabin luggage to determine and excess fees due?