Hi,
Well, I reach the correct total:
16.08+4.09+4.24=24.41
It's normal that it uses the rounded values for the total calculation since the "round prices during calculations" setting is turned on.
And as you can see in the screenshot, your "subtotal" is not what it should.
19.45075 rounded is 19.45 ; there is not possibility that it is rounded 19.46 unless there is something else in your website which can affect the prices.
pasteboard.co/1Zw4g7GF.png
I recommend you to update HikaShop with the latest package and to check your plugins and view overrides.
If you want to provide details about orders ; use screenshots from the backend. Emails are unfortunately, not helpful.
Regards,