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	$162.28	7.203%	$173.969	$173.97	$173.95	$174.00
Purchase #2	$123.80	7.850%	$133.5183	$133.52	$133.50	$133.50
Purchase #3	$38.45	10.599%	$42.5253	$42.53	$42.55	$42.50
Purchase #4	$183.28	3.511%	$189.715	$189.72	$189.70	$189.70
Purchase #5	$232.33	6.458%	$247.3339	$247.33	$247.35	$247.30
Purchase #6	$91.67	10.700%	$101.4787	$101.48	$101.50	$101.50
Purchase #7	$130.43	10.438%	$144.0443	$144.04	$144.05	$144.00
7 purchase totals =	$962.24		$1,032.5845	$1,032.59	$1,032.60	$1,032.50