shown price on frontend does not exactly match fixed price in backend

Dear Support Team,

thank you so much for the great plugin.

I use fixed prices for each product e.g. 9.80 €. On on the shop and product page however it shows 10.04 €.
Where does this small difference come from?

The usual price is 13.80 CHF (Swiss francs).

Thank you so much for your assistence.

Best wishes
Mario Kaiser