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	$94.42	5.541%	$99.6518	$99.65	$99.65	$99.70
Purchase #2	$186.32	4.552%	$194.8013	$194.80	$194.80	$194.80
Purchase #3	$15.81	10.460%	$17.4637	$17.46	$17.45	$17.50
Purchase #4	$152.56	6.512%	$162.4947	$162.49	$162.50	$162.50
Purchase #5	$156.48	5.674%	$165.3587	$165.36	$165.35	$165.40
Purchase #6	$188.26	3.654%	$195.139	$195.14	$195.15	$195.10
Purchase #7	$245.88	5.551%	$259.5288	$259.53	$259.55	$259.50
7 purchase totals =	$1,039.73		$1,094.4380	$1,094.43	$1,094.45	$1,094.50