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	$151.26	7.507%	$162.6151	$162.62	$162.60	$162.60
Purchase #2	$179.96	8.171%	$194.6645	$194.66	$194.65	$194.70
Purchase #3	$92.66	3.715%	$96.1023	$96.10	$96.10	$96.10
Purchase #4	$185.28	6.129%	$196.6358	$196.64	$196.65	$196.60
Purchase #5	$183.30	9.570%	$200.8418	$200.84	$200.85	$200.80
Purchase #6	$177.54	10.462%	$196.1142	$196.11	$196.10	$196.10
Purchase #7	$13.61	8.400%	$14.7532	$14.75	$14.75	$14.80
7 purchase totals =	$983.61		$1,061.7269	$1,061.72	$1,061.70	$1,061.70