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	$91.51	4.844%	$95.9427	$95.94	$95.95	$95.90
Purchase #2	$40.94	3.485%	$42.3668	$42.37	$42.35	$42.40
Purchase #3	$43.90	3.437%	$45.4088	$45.41	$45.40	$45.40
Purchase #4	$195.29	13.795%	$222.2303	$222.23	$222.25	$222.20
Purchase #5	$111.71	4.139%	$116.3337	$116.33	$116.35	$116.30
Purchase #6	$89.56	6.252%	$95.1593	$95.16	$95.15	$95.20
Purchase #7	$245.33	7.654%	$264.1076	$264.11	$264.10	$264.10
7 purchase totals =	$818.24		$881.5492	$881.55	$881.55	$881.50