Rounding problems when displaying prices with tax
In the admin interface, one needs to input the Produc price without tax. I suppose most shops do pricing by deciding the price with tax first. To get the expected price, one sometimes needs to add more decimals to the price with tax (e.g. to get 10,90 with tax, in admin one inputs 8,935). When products are added to the cart, sometimes the cart total and product (when more than 1 pcs) prices get rounded a bit wrong (e.g. I now see 92,09 which should be 92,10).
Rounding of shipping costs in tiered module is even worse, since it only accepts 2 decimals and can thus not always be input so as to round to the correct price with tax.
I would actually prefer to input prices with tax in the admin and calculate the prices without tax internally from them. Small rounding errors would not matter so much in that direction, since prices without tax aren't usually rounded like those presented to customers. I suppose this would be a rather large change, though, and don't know if the current behavior makes more sense in other countries.
Reported by teroajk