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	$182.83	6.249%	$194.255	$194.26	$194.25	$194.30
Purchase #2	$29.32	10.407%	$32.3713	$32.37	$32.35	$32.40
Purchase #3	$48.78	11.489%	$54.3843	$54.38	$54.40	$54.40
Purchase #4	$144.44	13.757%	$164.3106	$164.31	$164.30	$164.30
Purchase #5	$250.56	5.713%	$264.8745	$264.87	$264.85	$264.90
Purchase #6	$236.50	7.281%	$253.7196	$253.72	$253.70	$253.70
Purchase #7	$146.63	10.576%	$162.1376	$162.14	$162.15	$162.10
7 purchase totals =	$1,039.06		$1,126.0529	$1,126.05	$1,126.00	$1,126.10