Welcome again to the Community space, @docmartin. Let me clarify things for you.

The steps in enabling the insufficient quantity in QuickBooks Desktop aren't similar to QuickBooks Point of Sale. 

Currently, the option to enable insufficient quantity in QuickBooks Point of Sale is unavailable. We can only create reminders based on Available quantity and On Hand quantity.

You can also reach our POS support team for guidance on a possible alternative to help you with your concern. They have the necessary tools to check your account and help you further. For the steps, please check out this article: Contact Payments or Point of Sale Support.

I'm also adding this article to help import and export information in your file using MS Excel. This is a more efficient way of updating your data instead of doing it manually inside the software: QuickBooks Desktop Point of Sale: Import and Export overview.

Feel free to get back to this thread if you have further questions about enabling insufficient quantity in POS. I'll be around to assist you. Stay safe and take care!