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	$119.43	3.222%	$123.278	$123.28	$123.30	$123.30
Purchase #2	$114.64	7.418%	$123.144	$123.14	$123.15	$123.10
Purchase #3	$169.71	8.593%	$184.2932	$184.29	$184.30	$184.30
Purchase #4	$58.37	9.767%	$64.071	$64.07	$64.05	$64.10
Purchase #5	$191.28	6.681%	$204.0594	$204.06	$204.05	$204.10
Purchase #6	$154.54	6.164%	$164.0658	$164.07	$164.05	$164.10
Purchase #7	$185.34	5.560%	$195.6449	$195.64	$195.65	$195.60
7 purchase totals =	$993.31		$1,058.5563	$1,058.55	$1,058.55	$1,058.60