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	$62.43	10.450%	$68.9539	$68.95	$68.95	$69.00
Purchase #2	$120.41	5.529%	$127.0675	$127.07	$127.05	$127.10
Purchase #3	$194.70	12.552%	$219.1387	$219.14	$219.15	$219.10
Purchase #4	$235.58	5.846%	$249.352	$249.35	$249.35	$249.40
Purchase #5	$116.37	6.219%	$123.6071	$123.61	$123.60	$123.60
Purchase #6	$238.64	6.237%	$253.524	$253.52	$253.50	$253.50
Purchase #7	$20.73	10.381%	$22.882	$22.88	$22.90	$22.90
7 purchase totals =	$988.86		$1,064.5252	$1,064.52	$1,064.50	$1,064.60