Mephistopheles is also a lawful evil (also known as the �god of lawyers�). He does not lie and honors the contract to the letter. If the contract says 7000 souls, he will not take 7001 - it will be a breach of contract. The devil always honors the contract.

Besides, some who repeat the �holy� words never went through the path of the Ascension of Astarion. Or they didn't like the behavior and didn't play further. And when you really want to see the situation in a convenient way, your mind clings to any arguments. You don't want to check and analyze - suddenly the argument will turn out to be false, and the comfortable perception will be shaken.

One life, one love - until the world falls down.