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	$225.57	8.542%	$244.8382	$244.84	$244.85	$244.80
Purchase #2	$65.37	11.516%	$72.898	$72.90	$72.90	$72.90
Purchase #3	$66.44	8.424%	$72.0369	$72.04	$72.05	$72.00
Purchase #4	$71.59	8.478%	$77.6594	$77.66	$77.65	$77.70
Purchase #5	$179.65	3.723%	$186.3384	$186.34	$186.35	$186.30
Purchase #6	$154.78	7.765%	$166.7987	$166.80	$166.80	$166.80
Purchase #7	$174.77	11.218%	$194.3757	$194.38	$194.40	$194.40
7 purchase totals =	$938.17		$1,014.9453	$1,014.96	$1,015.00	$1,014.90