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	$197.35	5.630%	$208.4608	$208.46	$208.45	$208.50
Purchase #2	$197.97	6.632%	$211.0994	$211.10	$211.10	$211.10
Purchase #3	$108.47	5.415%	$114.3437	$114.34	$114.35	$114.30
Purchase #4	$122.56	4.256%	$127.7762	$127.78	$127.80	$127.80
Purchase #5	$96.30	8.673%	$104.6521	$104.65	$104.65	$104.70
Purchase #6	$181.44	9.208%	$198.147	$198.15	$198.15	$198.10
Purchase #7	$180.27	11.455%	$200.9199	$200.92	$200.90	$200.90
7 purchase totals =	$1,084.36		$1,165.3991	$1,165.40	$1,165.40	$1,165.40