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	$182.93	7.432%	$196.5254	$196.53	$196.55	$196.50
Purchase #2	$196.91	12.108%	$220.7519	$220.75	$220.75	$220.80
Purchase #3	$191.54	3.636%	$198.5044	$198.50	$198.50	$198.50
Purchase #4	$236.69	9.522%	$259.2276	$259.23	$259.25	$259.20
Purchase #5	$162.36	12.430%	$182.5413	$182.54	$182.55	$182.50
Purchase #6	$218.75	6.667%	$233.3341	$233.33	$233.35	$233.30
Purchase #7	$162.94	5.523%	$171.9392	$171.94	$171.95	$171.90
7 purchase totals =	$1,352.12		$1,462.8239	$1,462.82	$1,462.90	$1,462.70