Hi no10pin,
I am pleased to report that we have just released an update to resolve the latest issues you reported with the "Basic Edit" feature. As a result, the “Quantity” field should no longer be cleared out when you are editing auction format listings and remove one from the list, and you should be able to successfully schedule your items directly after completing your revisions.
If you notice any remaining issues of this nature, please don't hesitate to let us know!
-Mike