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	$196.44	6.313%	$208.8413	$208.84	$208.85	$208.80
Purchase #2	$74.70	4.421%	$78.0025	$78.00	$78.00	$78.00
Purchase #3	$152.82	9.368%	$167.1362	$167.14	$167.15	$167.10
Purchase #4	$211.55	5.272%	$222.7029	$222.70	$222.70	$222.70
Purchase #5	$64.92	4.633%	$67.9277	$67.93	$67.95	$67.90
Purchase #6	$78.45	5.843%	$83.0338	$83.03	$83.05	$83.00
Purchase #7	$223.85	5.370%	$235.8707	$235.87	$235.85	$235.90
7 purchase totals =	$1,002.73		$1,063.5151	$1,063.51	$1,063.55	$1,063.40