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	$211.51	3.798%	$219.5431	$219.54	$219.55	$219.50
Purchase #2	$7.38	7.480%	$7.932	$7.93	$7.95	$7.90
Purchase #3	$29.97	5.146%	$31.5123	$31.51	$31.50	$31.50
Purchase #4	$77.77	5.614%	$82.136	$82.14	$82.15	$82.10
Purchase #5	$190.37	11.852%	$212.9327	$212.93	$212.95	$212.90
Purchase #6	$117.25	4.598%	$122.6412	$122.64	$122.65	$122.60
Purchase #7	$42.85	7.450%	$46.0423	$46.04	$46.05	$46.00
7 purchase totals =	$677.10		$722.7396	$722.73	$722.80	$722.50