This was done to death months ago, you will just have to believe us we are right, i had to be convinced last year too.
You are allowed 20kg checked luggage, you paid for a bike, that can be up to 32kg and is exempt from excess luggage charges, it cant be any clearer than that
I went to the alps last year with the mountain bike, 25kg packed including spares and bag, 18kg of luggage, no excess charges and all weighed and accepted no problems
Just print the T&C's that i linked to, hightlight the part about no excess for bikes and if you get any trouble at check in, be polite, reference them to the T&C's and smile smugly, but not too smugly as they dont have to take you if they really dont want to !!