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	$176.95	9.557%	$193.8611	$193.86	$193.85	$193.90
Purchase #2	$247.95	6.238%	$263.4171	$263.42	$263.40	$263.40
Purchase #3	$58.34	6.231%	$61.9752	$61.98	$62.00	$62.00
Purchase #4	$124.92	6.412%	$132.9299	$132.93	$132.95	$132.90
Purchase #5	$214.59	3.557%	$222.223	$222.22	$222.20	$222.20
Purchase #6	$225.29	5.857%	$238.4852	$238.49	$238.50	$238.50
Purchase #7	$9.96	10.799%	$11.0356	$11.04	$11.05	$11.00
7 purchase totals =	$1,058.00		$1,123.9271	$1,123.94	$1,123.95	$1,123.90