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	$38.95	13.817%	$44.3317	$44.33	$44.35	$44.30
Purchase #2	$245.83	3.492%	$254.4144	$254.41	$254.40	$254.40
Purchase #3	$11.72	7.138%	$12.5566	$12.56	$12.55	$12.60
Purchase #4	$213.62	3.429%	$220.945	$220.95	$220.95	$220.90
Purchase #5	$93.84	11.248%	$104.3951	$104.40	$104.40	$104.40
Purchase #6	$207.40	5.740%	$219.3048	$219.30	$219.30	$219.30
Purchase #7	$174.27	12.758%	$196.5034	$196.50	$196.50	$196.50
7 purchase totals =	$985.63		$1,052.4510	$1,052.45	$1,052.45	$1,052.40