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	$88.49	6.155%	$93.9366	$93.94	$93.95	$93.90
Purchase #2	$12.57	10.346%	$13.8705	$13.87	$13.85	$13.90
Purchase #3	$42.88	6.742%	$45.771	$45.77	$45.75	$45.80
Purchase #4	$117.73	4.860%	$123.4517	$123.45	$123.45	$123.50
Purchase #5	$59.71	9.805%	$65.5646	$65.56	$65.55	$65.60
Purchase #6	$196.41	6.187%	$208.5619	$208.56	$208.55	$208.60
Purchase #7	$139.38	6.454%	$148.3756	$148.38	$148.40	$148.40
7 purchase totals =	$657.17		$699.5319	$699.53	$699.50	$699.70