Differences between Project XML and MPP files

Estate_Master -- I am not surprised at all by the fact that you see differences between the original project and a new project created from the exported XML file.  Based on my personal experience, the XML file does not capture the timephasing of task Work and Cost values on tasks.  And I suspect your use of the 24 Hour calendar is at least partially the source of the errors.

For me, the Save to XML option is a last resort to try to fix a corrupted project.  I know that using this feature will capture the "guts" of the project, but not the exact duplicate project.  Out of curiosity, why are you using the Save to XML feature?

Please let us know and we will try to help you.