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	$143.77	5.775%	$152.0727	$152.07	$152.05	$152.10
Purchase #2	$196.43	4.427%	$205.126	$205.13	$205.15	$205.10
Purchase #3	$142.77	11.167%	$158.7131	$158.71	$158.70	$158.70
Purchase #4	$203.63	3.504%	$210.7652	$210.77	$210.75	$210.80
Purchase #5	$72.64	13.146%	$82.1893	$82.19	$82.20	$82.20
Purchase #6	$105.83	5.490%	$111.6401	$111.64	$111.65	$111.60
Purchase #7	$81.26	11.612%	$90.6959	$90.70	$90.70	$90.70
7 purchase totals =	$946.33		$1,011.2023	$1,011.21	$1,011.20	$1,011.20