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	$222.60	8.570%	$241.6768	$241.68	$241.70	$241.70
Purchase #2	$49.65	5.322%	$52.2924	$52.29	$52.30	$52.30
Purchase #3	$80.84	6.230%	$85.8763	$85.88	$85.90	$85.90
Purchase #4	$84.62	5.828%	$89.5517	$89.55	$89.55	$89.60
Purchase #5	$160.82	10.758%	$178.121	$178.12	$178.10	$178.10
Purchase #6	$201.83	10.681%	$223.3875	$223.39	$223.40	$223.40
Purchase #7	$171.72	3.301%	$177.3885	$177.39	$177.40	$177.40
7 purchase totals =	$972.08		$1,048.2942	$1,048.30	$1,048.35	$1,048.40