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	$197.64	11.139%	$219.6551	$219.66	$219.65	$219.70
Purchase #2	$152.74	10.166%	$168.2675	$168.27	$168.25	$168.30
Purchase #3	$128.46	9.396%	$140.5301	$140.53	$140.55	$140.50
Purchase #4	$64.86	7.226%	$69.5468	$69.55	$69.55	$69.50
Purchase #5	$105.30	6.298%	$111.9318	$111.93	$111.95	$111.90
Purchase #6	$169.57	11.529%	$189.1197	$189.12	$189.10	$189.10
Purchase #7	$179.41	11.531%	$200.0978	$200.10	$200.10	$200.10
7 purchase totals =	$997.98		$1,099.1488	$1,099.16	$1,099.15	$1,099.10