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	$178.36	10.234%	$196.6134	$196.61	$196.60	$196.60
Purchase #2	$9.57	12.328%	$10.7498	$10.75	$10.75	$10.70
Purchase #3	$71.42	7.604%	$76.8508	$76.85	$76.85	$76.90
Purchase #4	$170.90	12.498%	$192.2591	$192.26	$192.25	$192.30
Purchase #5	$193.61	10.258%	$213.4705	$213.47	$213.45	$213.50
Purchase #6	$207.93	10.179%	$229.0952	$229.10	$229.10	$229.10
Purchase #7	$144.90	6.350%	$154.1012	$154.10	$154.10	$154.10
7 purchase totals =	$976.69		$1,073.1400	$1,073.14	$1,073.10	$1,073.20