I acknowledge how this feature is essential for your business needs, Epygi. In QuickBooks Online, you can still create price rules. However, applying them to the invoice in the new layout experience is unavailable. 

We don't have a specific timeframe for when this feature will be available in the new invoice experience. Our dedicated product development team will review your feedback and work on this concern. Your input is highly valued and appreciated. 

See the attached screenshot below if you want to send feedback. 

As a workaround, you can manually calculate the discount, create a service item for the markup, and then add it to your invoice.

To set up a service item:

1. Hover to the Sales menu and click the Products & services tab. 
2. Select New, then choose Service. Type in your preferred discount name. 
3. Enter the discount price or rate in the Sales price/rate section. (Ex. -0.10 for 1%). 
4. Pick Edit sales tax, then set the service item to Non-Taxable. Hit Done. 
5. Afterward, Save and close.

Now, let's add the discount item each time you select a product on the invoice page. Please see the attached screenshot for visual reference. 

Another alternative is to look for third-party apps that offer this feature as an alternative solution. 

Here's how to access it in your product: 

1. Click Apps from the left panel, then go to the Find Apps tab.
2. From the search bar, type in the keyword to look for an app.
3. Once done, you can choose an app from the lists that suits your business needs.  

Furthermore, you can visit these informative articles as a guide to managing your invoices:

• Customize invoices
• Record invoice payments.
• See what's new with estimates and invoices.

Rest assured that you can now work on your invoices promptly with the workaround provided. I'm always here to give any assistance you may need.