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	$211.65	7.564%	$227.6592	$227.66	$227.65	$227.70
Purchase #2	$180.82	7.728%	$194.7938	$194.79	$194.80	$194.80
Purchase #3	$182.98	7.466%	$196.6413	$196.64	$196.65	$196.60
Purchase #4	$199.89	13.650%	$227.175	$227.18	$227.20	$227.20
Purchase #5	$29.77	4.136%	$31.0013	$31.00	$31.00	$31.00
Purchase #6	$181.88	7.234%	$195.0372	$195.04	$195.05	$195.00
Purchase #7	$67.35	5.609%	$71.1277	$71.13	$71.15	$71.10
7 purchase totals =	$1,054.34		$1,143.4355	$1,143.44	$1,143.50	$1,143.40