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	$60.48	3.163%	$62.393	$62.39	$62.40	$62.40
Purchase #2	$74.59	10.807%	$82.6509	$82.65	$82.65	$82.70
Purchase #3	$72.33	5.291%	$76.157	$76.16	$76.15	$76.20
Purchase #4	$241.60	5.502%	$254.8928	$254.89	$254.90	$254.90
Purchase #5	$215.65	12.686%	$243.0074	$243.01	$243.00	$243.00
Purchase #6	$45.40	11.743%	$50.7313	$50.73	$50.75	$50.70
Purchase #7	$141.33	7.838%	$152.4074	$152.41	$152.40	$152.40
7 purchase totals =	$851.38		$922.2398	$922.24	$922.25	$922.30