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	$219.27	11.120%	$243.6528	$243.65	$243.65	$243.70
Purchase #2	$40.93	11.539%	$45.6529	$45.65	$45.65	$45.70
Purchase #3	$136.63	3.608%	$141.5596	$141.56	$141.55	$141.60
Purchase #4	$200.77	8.702%	$218.241	$218.24	$218.25	$218.20
Purchase #5	$132.60	9.692%	$145.4516	$145.45	$145.45	$145.50
Purchase #6	$22.96	9.512%	$25.144	$25.14	$25.15	$25.10
Purchase #7	$181.98	5.447%	$191.8925	$191.89	$191.90	$191.90
7 purchase totals =	$935.14		$1,011.5944	$1,011.58	$1,011.60	$1,011.70