The term round-trip is used in document conversion particularly involving markup languages such as XML and SGML.
Compound documents will frequently lose information on images and other embedded objects.
If the text file is converted back to the original format, information will necessarily be missing.
Some formats such as JPEG achieve compression through small amount of information loss.
Just because the initial and final documents are not bitwise identical does not mean there is information loss.
While this may be needed for some cases, the idea of a round-trip conversion is to go through another format representation or data structure and back again.