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	$167.48	4.465%	$174.958	$174.96	$174.95	$175.00
Purchase #2	$137.45	7.347%	$147.5485	$147.55	$147.55	$147.50
Purchase #3	$56.44	3.678%	$58.5159	$58.52	$58.50	$58.50
Purchase #4	$79.61	12.499%	$89.5605	$89.56	$89.55	$89.60
Purchase #5	$194.77	4.559%	$203.6496	$203.65	$203.65	$203.60
Purchase #6	$167.45	5.549%	$176.7418	$176.74	$176.75	$176.70
Purchase #7	$103.29	7.832%	$111.3797	$111.38	$111.40	$111.40
7 purchase totals =	$906.49		$962.3540	$962.36	$962.35	$962.30