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	$86.95	10.377%	$95.9728	$95.97	$95.95	$96.00
Purchase #2	$40.44	9.170%	$44.1483	$44.15	$44.15	$44.10
Purchase #3	$216.31	6.293%	$229.9224	$229.92	$229.90	$229.90
Purchase #4	$67.93	4.131%	$70.7362	$70.74	$70.75	$70.70
Purchase #5	$233.66	9.441%	$255.7198	$255.72	$255.70	$255.70
Purchase #6	$207.92	6.625%	$221.6947	$221.69	$221.70	$221.70
Purchase #7	$188.38	4.218%	$196.3259	$196.33	$196.35	$196.30
7 purchase totals =	$1,041.59		$1,114.5201	$1,114.52	$1,114.50	$1,114.40