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	$79.39	8.241%	$85.9325	$85.93	$85.95	$85.90
Purchase #2	$107.35	4.281%	$111.9457	$111.95	$111.95	$111.90
Purchase #3	$237.32	11.365%	$264.2914	$264.29	$264.30	$264.30
Purchase #4	$63.28	9.372%	$69.2106	$69.21	$69.20	$69.20
Purchase #5	$74.81	6.815%	$79.9083	$79.91	$79.90	$79.90
Purchase #6	$146.66	8.581%	$159.2449	$159.24	$159.25	$159.20
Purchase #7	$228.47	7.516%	$245.6418	$245.64	$245.65	$245.60
7 purchase totals =	$937.28		$1,016.1752	$1,016.17	$1,016.20	$1,016.00