Happy to have you here on the Community page, @MickeyK.
I'm here to share some information about the items added from the Item List and the alternative vendors in QuickBooks Desktop Enterprise.
When updating the items from the Item List, the changes are only applicable if you're about to create a transaction or for the incoming entries that you'll be creating. The update won't take effect on those transactions created before changing the cost or item name.
To learn more about this feature, check out this link: How to use alternate vendors in QuickBooks Enterprise Solutions.
Also, read the topics from this article for additional guides about managing your item list, vendors, and QuickBooks in the future.
I'm always here to help if you have any other questions. Just add a comment below. Keep safe, @MickeyK!
