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	$162.64	7.434%	$174.7307	$174.73	$174.75	$174.70
Purchase #2	$27.41	7.551%	$29.4797	$29.48	$29.50	$29.50
Purchase #3	$206.59	7.639%	$222.3714	$222.37	$222.35	$222.40
Purchase #4	$204.86	13.626%	$232.7742	$232.77	$232.75	$232.80
Purchase #5	$158.76	5.769%	$167.9189	$167.92	$167.90	$167.90
Purchase #6	$90.34	11.637%	$100.8529	$100.85	$100.85	$100.90
Purchase #7	$248.51	7.627%	$267.4639	$267.46	$267.45	$267.50
7 purchase totals =	$1,099.11		$1,195.5917	$1,195.58	$1,195.55	$1,195.70