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	$195.78	8.245%	$211.9221	$211.92	$211.90	$211.90
Purchase #2	$202.90	3.672%	$210.3505	$210.35	$210.35	$210.40
Purchase #3	$77.52	3.670%	$80.365	$80.37	$80.35	$80.40
Purchase #4	$43.42	13.424%	$49.2487	$49.25	$49.25	$49.20
Purchase #5	$179.39	3.263%	$185.2435	$185.24	$185.25	$185.20
Purchase #6	$209.28	6.346%	$222.5609	$222.56	$222.55	$222.60
Purchase #7	$47.28	7.453%	$50.8038	$50.80	$50.80	$50.80
7 purchase totals =	$955.57		$1,010.4945	$1,010.49	$1,010.45	$1,010.50