Hi there, @MK18.

Thanks for following up with us. 

I wanted to chime in to let you know that adding a class to the Exchange Gain Or Loss account is currently unavailable in QuickBooks Online. The Exchange Gain Or Loss is calculated once the payment is applied. You can only assign a class in the invoice and not at the time of payment.

You can see the help articles I've included below for further details:

• Frequently Asked Questions about Home Currency Adjustments.
• Change the accounting method.
• Differentiate Cash and Accrual basis.
• How to set up and use class and location tracking.

Please let me know if you have any follow up questions. I'm always around to lend a hand. Take care!