The fee example says $3.29, when it should say $3.3. Since according to the formulas in “Learn More” link, the fee amount should be $3.2955715756950000 - rounds up to 3.3…
I’m in the process of figuring out how to include CC processing fees after the sales tax (currently it is added before) - that throws off the math a bit, so I didn’t look into the rounding on actual invoices.