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	$195.26	13.866%	$222.3348	$222.33	$222.35	$222.30
Purchase #2	$211.68	3.195%	$218.4432	$218.44	$218.45	$218.40
Purchase #3	$11.69	5.266%	$12.3056	$12.31	$12.30	$12.30
Purchase #4	$117.74	10.860%	$130.5266	$130.53	$130.55	$130.50
Purchase #5	$65.95	11.105%	$73.2737	$73.27	$73.25	$73.30
Purchase #6	$208.72	12.248%	$234.284	$234.28	$234.30	$234.30
Purchase #7	$156.82	11.232%	$174.434	$174.43	$174.45	$174.40
7 purchase totals =	$967.86		$1,065.6019	$1,065.59	$1,065.65	$1,065.50