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	$215.26	10.375%	$237.5932	$237.59	$237.60	$237.60
Purchase #2	$58.85	11.309%	$65.5053	$65.51	$65.50	$65.50
Purchase #3	$193.25	3.741%	$200.4795	$200.48	$200.50	$200.50
Purchase #4	$64.88	6.740%	$69.2529	$69.25	$69.25	$69.30
Purchase #5	$143.49	4.777%	$150.3445	$150.34	$150.35	$150.30
Purchase #6	$94.98	9.418%	$103.9252	$103.93	$103.95	$103.90
Purchase #7	$185.63	10.860%	$205.7894	$205.79	$205.80	$205.80
7 purchase totals =	$956.34		$1,032.8900	$1,032.89	$1,032.95	$1,032.90