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	$196.78	7.782%	$212.0934	$212.09	$212.10	$212.10
Purchase #2	$13.46	5.732%	$14.2315	$14.23	$14.25	$14.20
Purchase #3	$64.26	5.674%	$67.9061	$67.91	$67.90	$67.90
Purchase #4	$70.32	11.837%	$78.6438	$78.64	$78.65	$78.60
Purchase #5	$111.27	12.316%	$124.974	$124.97	$124.95	$125.00
Purchase #6	$44.95	12.778%	$50.6937	$50.69	$50.70	$50.70
Purchase #7	$191.46	13.254%	$216.8361	$216.84	$216.85	$216.80
7 purchase totals =	$692.50		$765.3786	$765.37	$765.40	$765.30