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	$194.46	10.490%	$214.8589	$214.86	$214.85	$214.90
Purchase #2	$195.90	7.445%	$210.4848	$210.48	$210.50	$210.50
Purchase #3	$50.50	4.243%	$52.6427	$52.64	$52.65	$52.60
Purchase #4	$107.94	7.205%	$115.7171	$115.72	$115.70	$115.70
Purchase #5	$85.92	5.710%	$90.826	$90.83	$90.85	$90.80
Purchase #6	$167.28	13.160%	$189.294	$189.29	$189.30	$189.30
Purchase #7	$240.95	7.191%	$258.2767	$258.28	$258.30	$258.30
7 purchase totals =	$1,042.95		$1,132.1002	$1,132.10	$1,132.15	$1,132.10