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	$179.34	9.635%	$196.6194	$196.62	$196.60	$196.60
Purchase #2	$179.60	7.132%	$192.4091	$192.41	$192.40	$192.40
Purchase #3	$5.39	8.317%	$5.8383	$5.84	$5.85	$5.80
Purchase #4	$98.45	8.162%	$106.4855	$106.49	$106.50	$106.50
Purchase #5	$68.30	5.653%	$72.161	$72.16	$72.15	$72.20
Purchase #6	$230.85	4.821%	$241.9793	$241.98	$242.00	$242.00
Purchase #7	$195.85	10.617%	$216.6434	$216.64	$216.65	$216.60
7 purchase totals =	$957.78		$1,032.1360	$1,032.14	$1,032.15	$1,032.10