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	$175.81	11.504%	$196.0352	$196.04	$196.05	$196.00
Purchase #2	$103.42	8.104%	$111.8012	$111.80	$111.80	$111.80
Purchase #3	$168.53	3.731%	$174.8179	$174.82	$174.80	$174.80
Purchase #4	$130.29	12.543%	$146.6323	$146.63	$146.65	$146.60
Purchase #5	$132.72	4.446%	$138.6207	$138.62	$138.60	$138.60
Purchase #6	$146.96	12.285%	$165.014	$165.01	$165.00	$165.00
Purchase #7	$167.29	4.541%	$174.8866	$174.89	$174.90	$174.90
7 purchase totals =	$1,025.02		$1,107.8079	$1,107.81	$1,107.80	$1,107.70