Yet again your obsession with the word 'mantra'.
How do you know the account given by one waiter is correct ?
Because no other statement contradicts it for a start.
Because it fits with the overall tally of 14 bottles used by all the tables that night.
Because it matches the fact that none of the McCanns or their friends were reported by any witness that night as showing any effect on their behaviour of alcohol consumption.
Because the witness was present in the restaurant that night.
Because the witness was reporting something he was personally involved in dealing with.
Because there is no evidence that the witness is in any way unreliable.
Because most independent witnesses (as opposed to suspects) giving account of such banal matters as how many bottles of wine served do so honestly.
Because there is absolutely no evidence anywhere which suggests it is not the truth.
Because there is no logical reason why this independent witness should lie.
Now could you please outline your full reasons for disbelieving this statement?
Oh and for your information, I am using the word 'mantra' perfectly correctly when referring to the repetitive, unevidenced claims which you make. Perhaps you should look at a dictionary and then you would realise that?