Clarified checking repo size against source

README.md

@@ -93,7 +93,7 @@ Then list the files within to verify eveything is there:
 restic ls -p $REPO_PASSWORD -r /path/to/repo --long $SNAPSHOT_ID
 ```
 
-Then compare the backup size to the size of the source (this will retrieve the uncompressed size of the repo):
+Then compare the backup size to the size of the source. This will retrieve the uncompressed size of the repo, and it won't perfectly align. But it should give you an idea.
 
 ```bash
 restic ls -p $REPO_PASSWORD -r /path/to/repo stats $SNAPSHOT_ID