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	$179.60	8.576%	$195.0025	$195.00	$195.00	$195.00
Purchase #2	$82.37	8.327%	$89.2289	$89.23	$89.25	$89.20
Purchase #3	$250.34	8.809%	$272.3925	$272.39	$272.40	$272.40
Purchase #4	$174.29	8.206%	$188.5922	$188.59	$188.60	$188.60
Purchase #5	$72.64	7.387%	$78.0059	$78.01	$78.00	$78.00
Purchase #6	$38.66	9.505%	$42.3346	$42.33	$42.35	$42.30
Purchase #7	$134.37	3.728%	$139.3793	$139.38	$139.40	$139.40
7 purchase totals =	$932.27		$1,004.9359	$1,004.93	$1,005.00	$1,004.90