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	$202.52	4.656%	$211.9493	$211.95	$211.95	$211.90
Purchase #2	$209.83	5.447%	$221.2594	$221.26	$221.25	$221.30
Purchase #3	$110.38	13.311%	$125.0727	$125.07	$125.05	$125.10
Purchase #4	$114.69	11.829%	$128.2567	$128.26	$128.25	$128.30
Purchase #5	$40.71	11.471%	$45.3798	$45.38	$45.40	$45.40
Purchase #6	$145.66	12.623%	$164.0467	$164.05	$164.05	$164.00
Purchase #7	$195.73	10.152%	$215.6005	$215.60	$215.60	$215.60
7 purchase totals =	$1,019.52		$1,111.5651	$1,111.57	$1,111.55	$1,111.60