Hi there, RR_Will.

I appreciate you providing a detailed information on how transactions are made in QuickBooks. To help match the ACH payment from the Banking page, you'll first need to apply the credit to your invoices.

Here's how to apply the credit to bills.

1. Click + New.
2. Select Pay bills or Pay bill.
3. Select a bill for your vendor from the list. You'll see the available credit with this vendor in the Credit Applied field.
4. Complete the rest of the fields like you normally do.
5. Click Save and close

Once done, go to the Banking page and match the ACH payment to the remaining invoice balance of the vendor. Check out this article as your guide: Categorize and match online bank transactions in QuickBooks Online.

Let me know if you have additional questions by commenting below. I'll be right here to help manage your vendor's transactions.