Since you are flying trans-pacific, you will be allowed 2 pieces of checked luggage at 32kg max per piece. The extra piece will be charged at CAD142.00 per piece whether it's 5 kg or 32kg. Excess weight is charged at 3 times the excess piece, so a bag at 42kg will be charged 142.00 x 3 = 426.00. If it is both an excess in piece and weight, then you pay 426.00 + 142.00 = 568.00. I've heard a story of a passenger refusing to unpack an overweight bag and just to stick to her principle that she did not want to unpack, paid the 426.00 charge. Not worth it, IMHO.