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	$214.29	4.282%	$223.4659	$223.47	$223.45	$223.50
Purchase #2	$43.35	4.746%	$45.4074	$45.41	$45.40	$45.40
Purchase #3	$212.81	5.524%	$224.5656	$224.57	$224.55	$224.60
Purchase #4	$32.56	5.397%	$34.3173	$34.32	$34.30	$34.30
Purchase #5	$199.36	8.117%	$215.5421	$215.54	$215.55	$215.50
Purchase #6	$156.47	3.701%	$162.261	$162.26	$162.25	$162.30
Purchase #7	$146.86	5.120%	$154.3792	$154.38	$154.40	$154.40
7 purchase totals =	$1,005.70		$1,059.9385	$1,059.95	$1,059.90	$1,060.00