The changes to debian/changelog look incorrect here. Version 1.0.3+15.10.20150807-0ubuntu1 was released to the archive, so it shouldn't be replaced like this. Instead create a new stanza to describe what's new in this release.
The changes for the 1.0.0+15.10.20150805-0ubuntu1 changelog seem fine, assuming the build tools let it go.
The changes to debian/changelog look incorrect here. Version 1.0.3+15.
The changes for the 1.0.0+15.