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	$187.28	9.383%	$204.8525	$204.85	$204.85	$204.90
Purchase #2	$57.43	6.830%	$61.3525	$61.35	$61.35	$61.40
Purchase #3	$95.91	5.503%	$101.1879	$101.19	$101.20	$101.20
Purchase #4	$120.82	5.503%	$127.4687	$127.47	$127.45	$127.50
Purchase #5	$62.40	4.573%	$65.2536	$65.25	$65.25	$65.30
Purchase #6	$66.84	7.392%	$71.7808	$71.78	$71.80	$71.80
Purchase #7	$250.55	5.205%	$263.5911	$263.59	$263.60	$263.60
7 purchase totals =	$841.23		$895.4871	$895.48	$895.50	$895.70