I have no opinion on how you resolve it. Just only present one set of numbers to the public.
If the public see an 18 in the URL, they will call it 18th (第十八屆) in their media reports. Even if they see a conflicting number below, 3/4 will just assume it is a typo. The other 1/4 will assume the URL is a typo. And all will not be able to find the telephone number of a press contact to clarify before it is time for the story to hit the presses.
