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	$201.83	6.344%	$214.6341	$214.63	$214.65	$214.60
Purchase #2	$53.70	13.794%	$61.1074	$61.11	$61.10	$61.10
Purchase #3	$223.51	4.543%	$233.6641	$233.66	$233.65	$233.70
Purchase #4	$203.25	12.476%	$228.6075	$228.61	$228.60	$228.60
Purchase #5	$34.50	4.477%	$36.0446	$36.04	$36.05	$36.00
Purchase #6	$185.48	3.145%	$191.3133	$191.31	$191.30	$191.30
Purchase #7	$53.27	11.700%	$59.5026	$59.50	$59.50	$59.50
7 purchase totals =	$955.54		$1,024.8736	$1,024.86	$1,024.85	$1,024.80