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	$196.84	11.560%	$219.5947	$219.59	$219.60	$219.60
Purchase #2	$207.63	5.633%	$219.3258	$219.33	$219.35	$219.30
Purchase #3	$35.82	12.223%	$40.1983	$40.20	$40.20	$40.20
Purchase #4	$163.60	13.589%	$185.8316	$185.83	$185.85	$185.80
Purchase #5	$204.27	8.470%	$221.5717	$221.57	$221.55	$221.60
Purchase #6	$87.41	9.312%	$95.5496	$95.55	$95.55	$95.50
Purchase #7	$40.64	7.724%	$43.779	$43.78	$43.80	$43.80
7 purchase totals =	$936.21		$1,025.8507	$1,025.85	$1,025.90	$1,025.80