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	$144.93	5.401%	$152.7577	$152.76	$152.75	$152.80
Purchase #2	$84.46	12.459%	$94.9829	$94.98	$95.00	$95.00
Purchase #3	$112.40	3.145%	$115.935	$115.94	$115.95	$115.90
Purchase #4	$67.43	13.523%	$76.5486	$76.55	$76.55	$76.50
Purchase #5	$156.68	7.316%	$168.1427	$168.14	$168.15	$168.10
Purchase #6	$171.31	11.680%	$191.319	$191.32	$191.30	$191.30
Purchase #7	$210.70	5.536%	$222.3644	$222.36	$222.35	$222.40
7 purchase totals =	$947.91		$1,022.0503	$1,022.05	$1,022.05	$1,022.00