Hi VonDos,
I had a look into your files, and I must say that this time the problem isn't caused by erroneously split edges, but by some surfaces not being totally flat.
I can fix the problem easily, but maybe it is better if you send me the whole model (or at least the whole superstructure) for me to make sure that the perimetral vertices of the flattened surfaces will match perfectly the corresponding vertices of adjoining faces.
Sorry for making you to send the files twice, but as I said, at the beginning I thought the problem had a different cause
