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	$46.29	4.232%	$48.249	$48.25	$48.25	$48.20
Purchase #2	$83.41	6.149%	$88.5389	$88.54	$88.55	$88.50
Purchase #3	$248.91	4.272%	$259.5434	$259.54	$259.55	$259.50
Purchase #4	$20.37	9.124%	$22.2286	$22.23	$22.25	$22.20
Purchase #5	$207.61	11.150%	$230.7585	$230.76	$230.75	$230.80
Purchase #6	$142.64	7.738%	$153.6775	$153.68	$153.70	$153.70
Purchase #7	$211.64	5.148%	$222.5352	$222.54	$222.55	$222.50
7 purchase totals =	$960.87		$1,025.5311	$1,025.54	$1,025.60	$1,025.40