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	$191.56	11.134%	$212.8883	$212.89	$212.90	$212.90
Purchase #2	$77.34	11.781%	$86.4514	$86.45	$86.45	$86.50
Purchase #3	$66.43	7.715%	$71.5551	$71.56	$71.55	$71.60
Purchase #4	$83.54	8.839%	$90.9241	$90.92	$90.90	$90.90
Purchase #5	$233.38	11.550%	$260.3354	$260.34	$260.35	$260.30
Purchase #6	$140.83	5.583%	$148.6925	$148.69	$148.70	$148.70
Purchase #7	$146.49	4.197%	$152.6382	$152.64	$152.65	$152.60
7 purchase totals =	$939.57		$1,023.4850	$1,023.49	$1,023.50	$1,023.50