Hi there,
Thanks for reaching out with your question here in the Community.
I know there are times when you'll need to have two different taxes calculated on your products and services. You're able to do this by grouping the taxes together, rather than adding two tax codes separately.
To create a group sales tax rate, take a look at this article: How do I add a group sales tax rate? This article will help guide you through this process step-by-step.
In regards to adding two separate tax codes to your transaction individually, I'd recommend submitting feedback about this to our product engineers. To do that, click the Gear icon > Feedback.
If you have any other questions, please let me know.
Have a great day!