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	$219.69	3.352%	$227.054	$227.05	$227.05	$227.10
Purchase #2	$5.66	10.425%	$6.2501	$6.25	$6.25	$6.30
Purchase #3	$49.33	10.775%	$54.6453	$54.65	$54.65	$54.60
Purchase #4	$83.39	7.755%	$89.8569	$89.86	$89.85	$89.90
Purchase #5	$204.49	4.151%	$212.9784	$212.98	$213.00	$213.00
Purchase #6	$109.46	7.216%	$117.3586	$117.36	$117.35	$117.40
Purchase #7	$27.33	5.573%	$28.8531	$28.85	$28.85	$28.90
7 purchase totals =	$699.35		$736.9964	$737.00	$737.00	$737.20