Need four decimal pricing but two decimals for subtotals & totals

I have four decimal pricing in my store. Does anybody know how to keep the four decimals for the prices, but have only two decimals for the subtotals & totals once added to the cart.

for example, item a is .0434. if somebody adds 10 to the cart, i want the cart to show:

item A $.0434 x 10 = $4.34

I would also like for my shipping rates to be shown as two decimals

I am sure that this can be changed in fn_format_price, but I am just not sure of all of the places that i would have to change it.

thanks in advance for anybody that can help.