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	$174.58	10.508%	$192.9249	$192.92	$192.90	$192.90
Purchase #2	$145.43	12.807%	$164.0552	$164.06	$164.05	$164.10
Purchase #3	$210.57	8.665%	$228.8159	$228.82	$228.80	$228.80
Purchase #4	$57.60	13.781%	$65.5379	$65.54	$65.55	$65.50
Purchase #5	$145.94	4.131%	$151.9688	$151.97	$151.95	$152.00
Purchase #6	$86.89	10.456%	$95.9752	$95.98	$96.00	$96.00
Purchase #7	$126.38	5.552%	$133.3966	$133.40	$133.40	$133.40
7 purchase totals =	$947.39		$1,032.6745	$1,032.69	$1,032.65	$1,032.70