Unfortunaltely, @MLawson5 asked "How to edit in mass Line Items that are already in a deal", which is not possible with the link you provide. Line Items cannot be edited in bulk via the import method. Do you other ressources that could be helpful ? 🙂 I urgely need it
Currently, there is a way to bulk edit records, including properties in deals! I would like to share this knowledge base here with more information about it.