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	$214.38	5.352%	$225.8536	$225.85	$225.85	$225.90
Purchase #2	$55.55	6.801%	$59.328	$59.33	$59.35	$59.30
Purchase #3	$74.79	5.870%	$79.1802	$79.18	$79.20	$79.20
Purchase #4	$209.77	8.412%	$227.4159	$227.42	$227.40	$227.40
Purchase #5	$226.67	8.239%	$245.3453	$245.35	$245.35	$245.30
Purchase #6	$67.91	9.681%	$74.4844	$74.48	$74.50	$74.50
Purchase #7	$219.73	4.640%	$229.9255	$229.93	$229.95	$229.90
7 purchase totals =	$1,068.80		$1,141.5329	$1,141.54	$1,141.60	$1,141.50