While I can't disagree - this is a working database that I can't (for risks to the business) make wholesale changes to the format.
Some of what you say couldn't work (but the majority is fair).
From where I am here and now though was hoping that if a more generic piece of code:
DoCmd.RunSQL...
I can't deny that there is almost certainly a lot of that - come from a spreadsheet background. And a fair bit of VBA.
The deal record table has lines for each "deal" that we do. Each of these deals can be invoiced to both a buyer and a seller. Then when invoice there is an invoice created to a...
