The differences you described are due to the SharePoint list column's design. The only difference between rich text and enhanced rich text in our editor is the extra line of tools from the tools file. The editor outputs the same HTML in both cases. After the content is saved, SharePoint applies a number of filters that strip HTML tags that are not allowed in the current list column. If the column type is "rich text", the allowed tags are very few - just simple formatting. If the column type is "enhanced rich text", then you have more allowed tags. Unfortunately, we cannot control the content that is saved on the server because the tag stripping is done after it leaves the editor. Therefore if you need to have additional formatting in a "rich text" column, you should find a way to change it to "enhanced rich text".
the Telerik team