Can Finance Charges be assessed in the Online QB version similar to the desktop version?

Yes, David. Allow me to go into detail on how you can assess finance charges in QuickBooks Online (QBO) similar to QuickBooks Desktop (QBDT).

In QBO, it's possible to automate the process of adding service charges or late fees to customers. This way, you can set the fee amount and when to apply it to the invoices. Then, the system will calculate and automatically add the fee as a line item to any overdue invoices.

Please see the steps below to set up the default late fee setting:

1. Go to the Gear icon and select Account and Settings.
2. Click Sales, then select the pencil icon in the Late Fees section.
3. Switch on the Default charge applied to overdue invoices.
4. Enter the Amount and/or the Percent (%) of the fee.
5. Choose the Frequency and how often you charge customers.
6. Click Save, then Done.

Here's an article for the full details: Apply late fees to overdue invoices automatically in QuickBooks Online.

When your customer makes a payment, you'll need to record it in QBO to mark the invoice as paid. 

Keep in touch if you need further assistance with finance charges. I'll respond promptly to provide support. Take care, and have a great rest of the day.