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	$194.53	7.250%	$208.6334	$208.63	$208.65	$208.60
Purchase #2	$214.33	4.229%	$223.394	$223.39	$223.40	$223.40
Purchase #3	$202.40	12.438%	$227.5745	$227.57	$227.55	$227.60
Purchase #4	$170.54	12.240%	$191.4141	$191.41	$191.40	$191.40
Purchase #5	$40.95	7.196%	$43.8968	$43.90	$43.90	$43.90
Purchase #6	$166.95	5.208%	$175.6448	$175.64	$175.65	$175.60
Purchase #7	$35.78	10.263%	$39.4521	$39.45	$39.45	$39.50
7 purchase totals =	$1,025.48		$1,110.0097	$1,109.99	$1,110.00	$1,110.00