i've said it before & i'll say it again, it all depends on the person checking you in....
the craziest experience i had was last year when i was flying from lhr-del....ideally the allowance is 28 kgs but because i was traveling in first, it went up to 69 kgs....i'm plat so i was allowed an additional 20kgs....i also have the jet plat card from citibank which gave me an extra 15 kgs (normally they don't allow this on international flights but the supervisor at check-in was really nice & she allowed it)....so i was allowed a total of 104 kgs....
even after all this extra allowance, my luggage was about 10 kgs overweight....all thanks to the 2 heavy bags of books & files i had carried for my arbitration....plus i had another bag full of shopping items that my wife asked me to get back....
i was ready to pay the excess baggage fee but the supervisor just let me go....very sweet of her for first including the extra allowance from my credit card & then waiving off the 10 kgs extra....