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	$184.94	3.798%	$191.964	$191.96	$191.95	$192.00
Purchase #2	$10.68	11.305%	$11.8874	$11.89	$11.90	$11.90
Purchase #3	$159.61	7.799%	$172.058	$172.06	$172.05	$172.10
Purchase #4	$218.35	13.771%	$248.419	$248.42	$248.40	$248.40
Purchase #5	$150.69	6.191%	$160.0192	$160.02	$160.00	$160.00
Purchase #6	$98.44	6.522%	$104.8603	$104.86	$104.85	$104.90
Purchase #7	$148.54	11.599%	$165.7692	$165.77	$165.75	$165.80
7 purchase totals =	$971.25		$1,054.9771	$1,054.98	$1,054.90	$1,055.10