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	$69.44	8.633%	$75.4348	$75.43	$75.45	$75.40
Purchase #2	$211.51	12.562%	$238.0799	$238.08	$238.10	$238.10
Purchase #3	$19.62	11.851%	$21.9452	$21.95	$21.95	$21.90
Purchase #4	$208.83	6.421%	$222.239	$222.24	$222.25	$222.20
Purchase #5	$154.60	4.730%	$161.9126	$161.91	$161.90	$161.90
Purchase #6	$101.70	9.391%	$111.2506	$111.25	$111.25	$111.30
Purchase #7	$247.85	6.841%	$264.8054	$264.81	$264.80	$264.80
7 purchase totals =	$1,013.55		$1,095.6675	$1,095.67	$1,095.70	$1,095.60