Australian 1c or 2 currency were phased out in 1990s and are cost money to make for lower value. It doesn't make sense at all!
* round down to the nearest multiple of 5 cents for sales ending in 1c, 2c, 6c, 7c
* round up to the nearest multiple of 5 cents for sales ending in 3c, 4c, 8c, 9c...