He said that you should not delete or remove the original disavow file when uploading a new one. He said instead, upload the new one, which will replace the old disavow file. The reason he said was because when you delete the old one and upload a new one, it generates two emails to the Google team and may confuse them when review manual actions.
Here are his tweets:
As you can see, I am making an assumption that the “folks” being confused are those at Google who review reconsideration requests.
So as a note, when you go ahead and revise your disavow files, make sure you just replace it and not delete the original one.
For more details, see our Disavow link tool category.