[Koha] Updating ebook records in Koha - what happens to adjusted biblio records?

[Hartman, David W. - GBTS Library]

My library subscribes to Books24x7 and Safari Books online.  When  I update my collection to have the latest book records from these providers, I assume I should REVERT the last batch input and IMPORT the latest records.

If I took an existing Safari biblio record and added a print (second copy) to this existing record, would the print item (second copy) and biblio record disappear when I REVERT the Safari record, or would the biblio and item record remain for the one print copy?

Let me know .. I do not want to start the updating process without understanding its impact to revert and import updates.