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	$58.56	7.287%	$62.8273	$62.83	$62.85	$62.80
Purchase #2	$223.79	13.562%	$254.1404	$254.14	$254.15	$254.10
Purchase #3	$73.49	13.161%	$83.162	$83.16	$83.15	$83.20
Purchase #4	$199.57	7.176%	$213.8911	$213.89	$213.90	$213.90
Purchase #5	$210.94	6.153%	$223.9191	$223.92	$223.90	$223.90
Purchase #6	$237.46	9.377%	$259.7266	$259.73	$259.75	$259.70
Purchase #7	$19.73	5.469%	$20.809	$20.81	$20.80	$20.80
7 purchase totals =	$1,023.54		$1,118.4755	$1,118.48	$1,118.50	$1,118.40