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	$187.75	4.272%	$195.7707	$195.77	$195.75	$195.80
Purchase #2	$104.36	5.188%	$109.7742	$109.77	$109.75	$109.80
Purchase #3	$10.27	13.466%	$11.653	$11.65	$11.65	$11.70
Purchase #4	$55.58	10.769%	$61.5654	$61.57	$61.55	$61.60
Purchase #5	$92.83	4.302%	$96.8235	$96.82	$96.80	$96.80
Purchase #6	$117.25	8.439%	$127.1447	$127.14	$127.15	$127.10
Purchase #7	$122.89	7.169%	$131.7	$131.70	$131.70	$131.70
7 purchase totals =	$690.93		$734.4315	$734.42	$734.35	$734.50