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	$44.84	3.623%	$46.4646	$46.46	$46.45	$46.50
Purchase #2	$129.29	7.654%	$139.1859	$139.19	$139.20	$139.20
Purchase #3	$30.63	9.695%	$33.5996	$33.60	$33.60	$33.60
Purchase #4	$148.34	11.607%	$165.5578	$165.56	$165.55	$165.60
Purchase #5	$187.59	4.715%	$196.4349	$196.43	$196.45	$196.40
Purchase #6	$218.74	7.769%	$235.7339	$235.73	$235.75	$235.70
Purchase #7	$188.44	8.866%	$205.1471	$205.15	$205.15	$205.10
7 purchase totals =	$947.87		$1,022.1238	$1,022.12	$1,022.15	$1,022.10