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	$195.71	10.237%	$215.7448	$215.74	$215.75	$215.70
Purchase #2	$78.64	13.790%	$89.4845	$89.48	$89.50	$89.50
Purchase #3	$85.68	12.667%	$96.5331	$96.53	$96.55	$96.50
Purchase #4	$90.32	11.491%	$100.6987	$100.70	$100.70	$100.70
Purchase #5	$191.38	3.191%	$197.4869	$197.49	$197.50	$197.50
Purchase #6	$201.84	13.476%	$229.04	$229.04	$229.05	$229.00
Purchase #7	$170.78	6.500%	$181.8807	$181.88	$181.90	$181.90
7 purchase totals =	$1,014.35		$1,110.8687	$1,110.86	$1,110.95	$1,110.80