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	$202.54	8.192%	$219.1321	$219.13	$219.15	$219.10
Purchase #2	$221.36	13.577%	$251.414	$251.41	$251.40	$251.40
Purchase #3	$179.35	9.220%	$195.8861	$195.89	$195.90	$195.90
Purchase #4	$57.95	3.309%	$59.8676	$59.87	$59.85	$59.90
Purchase #5	$160.46	9.297%	$175.378	$175.38	$175.40	$175.40
Purchase #6	$172.46	13.873%	$196.3854	$196.39	$196.40	$196.40
Purchase #7	$234.75	9.284%	$256.5442	$256.54	$256.55	$256.50
7 purchase totals =	$1,228.87		$1,354.6074	$1,354.61	$1,354.65	$1,354.60