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	$178.26	8.806%	$193.9576	$193.96	$193.95	$194.00
Purchase #2	$72.85	8.355%	$78.9366	$78.94	$78.95	$78.90
Purchase #3	$52.71	4.483%	$55.073	$55.07	$55.05	$55.10
Purchase #4	$248.54	10.654%	$275.0195	$275.02	$275.00	$275.00
Purchase #5	$236.38	3.655%	$245.0197	$245.02	$245.00	$245.00
Purchase #6	$167.27	6.753%	$178.5657	$178.57	$178.55	$178.60
Purchase #7	$53.90	13.281%	$61.0585	$61.06	$61.05	$61.10
7 purchase totals =	$1,009.91		$1,087.6306	$1,087.64	$1,087.55	$1,087.70