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	$195.88	7.663%	$210.8903	$210.89	$210.90	$210.90
Purchase #2	$192.27	6.276%	$204.3369	$204.34	$204.35	$204.30
Purchase #3	$61.74	9.705%	$67.7319	$67.73	$67.75	$67.70
Purchase #4	$49.68	6.348%	$52.8337	$52.83	$52.85	$52.80
Purchase #5	$200.71	4.784%	$210.312	$210.31	$210.30	$210.30
Purchase #6	$16.89	6.860%	$18.0487	$18.05	$18.05	$18.00
Purchase #7	$236.57	5.192%	$248.8527	$248.85	$248.85	$248.90
7 purchase totals =	$953.74		$1,013.0062	$1,013.00	$1,013.05	$1,012.90