Hello there, @Thayer2.

I'll help share a few insights about the billable time entry format on printed invoices in QuickBooks Online (QBO). Then, guide you in sending product recommendations to help improve the features of our products and be added to the list of users that needs this specific option.

For the time being, you can set up the time in HH:MM format on fields that require hours, such as timesheets and paychecks in QBO. However, for invoices, the available column is Quantity. That's why when you add time, QuickBooks automatically converts it to decimals.

On the other hand, I can see how the benefit of being able to use and print billable entries in HH:MM format on invoices would aid you in managing your transactions with QBO. With this, I would encourage you to send suggestions or product recommendations. We take your suggestions as opportunities to improve the various features of our products.

Your valuable feedback will be forwarded and reviewed by our Product Development team to help improve your experience while using the program. Here's how:

1. Go to the Gear icon.
2. Select Feedback.
3. Type in your recommendation in the Share your feedback field.
4. Click Next.
5. Follow the on-screen instructions to complete the process. 

Also, you may want to check out one of our Help pages as your reference in managing your customers, invoicing, payments, and handling sales transactions using QBO: Customers and income help articles for QuickBooks Online.

On top of that, I'd also recommend visiting this page to keep you updated with the latest software improvements and enhancements with QBO: Customer Feedback for QuickBooks Online.

Let me know if you have other feature concerns or questions about managing invoices and sales transactions in QBO. Please don't hesitate to drop a comment below, and I'll gladly help. Take care, and I wish you continued success, Thayer2.