Why not create that record directly in the history table? A portal to that table from Products could be used and then the user enters the quantity on hand directly into a field in the portal--creating the new record in the history table automatically.
You may also find this thread on using an "inventory ledger" or "transactions table" to log inventory changes helpful: Managing Inventory using a Transactions Ledger
Well of course.
Thank you once again for your guidance. I am constantly amazed by my ability to tie myself into needless knots.
Your referenced post re Inventory Ledger is terrific. Thanks for that. I'll try to implement it and will no doubt have questions which I'll post over there?
Better to post your questions here where they can be kept separate from the posts already in that other thread.