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	$209.49	11.246%	$233.0492	$233.05	$233.05	$233.00
Purchase #2	$88.91	11.812%	$99.412	$99.41	$99.40	$99.40
Purchase #3	$110.73	12.168%	$124.2036	$124.20	$124.20	$124.20
Purchase #4	$191.67	3.745%	$198.848	$198.85	$198.85	$198.80
Purchase #5	$166.76	10.705%	$184.6117	$184.61	$184.60	$184.60
Purchase #6	$155.38	10.326%	$171.4245	$171.42	$171.40	$171.40
Purchase #7	$144.35	7.531%	$155.221	$155.22	$155.20	$155.20
7 purchase totals =	$1,067.29		$1,166.7700	$1,166.76	$1,166.70	$1,166.60