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	$167.57	11.428%	$186.7199	$186.72	$186.70	$186.70
Purchase #2	$5.52	5.253%	$5.81	$5.81	$5.80	$5.80
Purchase #3	$170.82	12.242%	$191.7318	$191.73	$191.75	$191.70
Purchase #4	$201.51	13.788%	$229.2942	$229.29	$229.30	$229.30
Purchase #5	$64.52	11.473%	$71.9224	$71.92	$71.90	$71.90
Purchase #6	$242.32	5.613%	$255.9214	$255.92	$255.90	$255.90
Purchase #7	$145.38	5.687%	$153.6478	$153.65	$153.65	$153.60
7 purchase totals =	$997.64		$1,095.0475	$1,095.04	$1,095.00	$1,094.90