Welcome to the Community, @apratt1.
I would love to help you, but I need more information to provide accurate solutions. Could you tell us which specific rounding issues you encountered on your invoice? Any screenshots you may have would also be helpful in assisting us to determine the best solution.
In the meantime, you can check out this guide for recording invoice payments: Record invoice payments in QuickBooks Online.
I'll be waiting for your response. Have a great day ahead!
