Atlantis Word Processor generates proper ePub files according to the ePub specification. You can validate .epub files of Atlantis with the online ePub validator:
http://www.threepress.org/document/epub-validate/
But you cannot be sure that your .epub file displays correctly (as intended by you) in a given eBook reader without testing it with this eBook reader. The ePub specification says how to generate .epub files. It says which elements are allowed in XHTMLs and which files can be included in an ePub package. But no ePub reader supports the ePub standard completely.
There is no such thing as "ePub for Mobile ADE". There is a single ePub standard. But any ePub book should be tested with the target ePub readers. Atlantis Word Processor could not know if a particular ePub book will display correctly on specific ePub readers. Again, the only way to find out if corrections to the formatting of the source document are needed is by testing your ePub files with your ePub reader software/device.