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	$190.67	7.288%	$204.566	$204.57	$204.55	$204.60
Purchase #2	$150.36	11.465%	$167.5988	$167.60	$167.60	$167.60
Purchase #3	$173.57	12.613%	$195.4624	$195.46	$195.45	$195.50
Purchase #4	$6.82	3.863%	$7.0835	$7.08	$7.10	$7.10
Purchase #5	$244.70	8.424%	$265.3135	$265.31	$265.30	$265.30
Purchase #6	$111.25	3.304%	$114.9257	$114.93	$114.95	$114.90
Purchase #7	$56.74	4.812%	$59.4703	$59.47	$59.45	$59.50
7 purchase totals =	$934.11		$1,014.4202	$1,014.42	$1,014.40	$1,014.50