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	$190.32	3.457%	$196.8994	$196.90	$196.90	$196.90
Purchase #2	$178.80	9.839%	$196.3921	$196.39	$196.40	$196.40
Purchase #3	$71.78	6.636%	$76.5433	$76.54	$76.55	$76.50
Purchase #4	$174.55	13.783%	$198.6082	$198.61	$198.60	$198.60
Purchase #5	$95.52	12.674%	$107.6262	$107.63	$107.65	$107.60
Purchase #6	$158.73	4.257%	$165.4871	$165.49	$165.50	$165.50
Purchase #7	$222.86	10.687%	$246.677	$246.68	$246.70	$246.70
7 purchase totals =	$1,092.56		$1,188.2333	$1,188.24	$1,188.30	$1,188.20