The extra KG allowance is intended ONLY for weight concept flights...piece concept currently remains at 2 x 32kg/70lbs for all passengers. However, the FB benefit is incorrectly written and does not specify weight concept only, so passengers are currently being given the benefit of this error in most situations (but discouraged, as 32kg is already a HEAVY bag that can break apart, lose a handle, damage equipment & other bags, and injure staff). Expect to see it clarified in the future.

Regarding the drop in piece concept allowances, AF has planned twice in the last 2 years to reduce the maximum to 2 x 23kg/50lbs per passenger, but it never gained IATA approval and was abandoned. It will be interesting to see if KL manages to go through with it. If so, then I expect the extra KG allowance will be "officially" in effect for elite/+ members on piece concept flights also.