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	$162.26	7.707%	$174.7654	$174.77	$174.75	$174.80
Purchase #2	$174.52	9.698%	$191.4449	$191.44	$191.45	$191.40
Purchase #3	$120.54	6.603%	$128.4993	$128.50	$128.50	$128.50
Purchase #4	$122.86	7.121%	$131.6089	$131.61	$131.60	$131.60
Purchase #5	$149.96	4.108%	$156.1204	$156.12	$156.10	$156.10
Purchase #6	$77.70	6.577%	$82.8103	$82.81	$82.80	$82.80
Purchase #7	$145.31	10.226%	$160.1694	$160.17	$160.15	$160.20
7 purchase totals =	$953.15		$1,025.4186	$1,025.42	$1,025.35	$1,025.40