When adding an expense or explaining a transaction, I often select Auto (or 20%) for example. However, I then don’t get to see what the monetary value is until I’ve submitted it. Can you just show the preview amount immediately so I know it’s correct? Here’s a little mockup to explain what I mean.
Hello 
Thanks for reaching out to us on this.
Showing the sales tax amount as a preview is not something we currently support I’m afraid. I can certainly see how that might be beneficial, and will pass this on to the product manager and engineering team that owns this area.
Cheers,
Stu McEwan
API Product Manager