Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$105.34	8.354%	$114.1401	$114.14	$114.15	$114.10
Purchase #2	$10.40	8.510%	$11.285	$11.29	$11.30	$11.30
Purchase #3	$100.31	13.818%	$114.1708	$114.17	$114.15	$114.20
Purchase #4	$80.80	13.599%	$91.788	$91.79	$91.80	$91.80
Purchase #5	$48.35	9.842%	$53.1086	$53.11	$53.10	$53.10
Purchase #6	$71.84	13.152%	$81.2884	$81.29	$81.30	$81.30
Purchase #7	$60.55	10.163%	$66.7037	$66.70	$66.70	$66.70
7 purchase totals =	$477.59		$532.4846	$532.49	$532.50	$532.50