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	$58.57	6.838%	$62.575	$62.58	$62.60	$62.60
Purchase #2	$193.57	3.515%	$200.374	$200.37	$200.35	$200.40
Purchase #3	$142.31	6.443%	$151.479	$151.48	$151.50	$151.50
Purchase #4	$191.35	5.307%	$201.5049	$201.50	$201.50	$201.50
Purchase #5	$74.33	6.773%	$79.3644	$79.36	$79.35	$79.40
Purchase #6	$190.93	10.444%	$210.8707	$210.87	$210.85	$210.90
Purchase #7	$196.81	4.266%	$205.2059	$205.21	$205.20	$205.20
7 purchase totals =	$1,047.87		$1,111.3739	$1,111.37	$1,111.35	$1,111.50