We all owe a lot to this guy, for timely and qualified solutions that he provide.
We have been facing this issue long time now. When we delete a Parent Transaction, the dependent Extender Information is orphaned and we do not know that. Over a period of time, this gets accumulated and lots of junk.
David nails this issue with his solution. Read it here: Removing Extender Data When Deleting Transactions or Lines.
This is very critical reference and we MUST treasure this. And I sincerely mean it.