You're already on the right track in applying price rules in your invoices in QuickBooks Online (QBO), @andreahalliday. Let me share a few details about this.

I can see how the benefit of being able to do price rules on billable time entered in timesheets would aid you in running the business with QBO. However, the option to do so isn't currently available. You'll have to manually enter the service item to apply a price rule.

We take customer suggestions as opportunities to improve the various features of our products. Therefore, I would encourage you to send suggestions or product recommendations.

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.

I've attached screenshots below that show the first four steps.

Also, to learn more about price rules and how you can customize your invoices in QBO, I'd recommend checking out these articles: 

• Customize invoices, estimates, and sales receipts in QuickBooks Online
• Set price rules in 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.

I'm all ears if you have other concerns about managing invoices and price rules in QBO. You can drop a comment below, and I'll gladly help. Take care, and I wish you continued success, @andreahalliday.