I dont know of a currency in the world where they dont have a unit for .01

if everything has to be in multiples of 5 and have a tax to incorperate rounding. its just going to make things complicated and it will seem weird to the rest of the world.

it costs $.0123 to make a penny. if the government is concered about their $.0023 per penny, then they can just figure out a slightly more effiecent way to manufacture it. Such as make a penny 10% thinner or 10% smaller diameter... something like that.

I guess also we have to know exactly how many pennies are produced each year to see the actual amount extra it costs them.