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	$194.50	7.695%	$209.4668	$209.47	$209.45	$209.50
Purchase #2	$208.63	7.778%	$224.8572	$224.86	$224.85	$224.90
Purchase #3	$91.82	3.161%	$94.7224	$94.72	$94.70	$94.70
Purchase #4	$88.26	11.208%	$98.1522	$98.15	$98.15	$98.20
Purchase #5	$240.27	10.119%	$264.5829	$264.58	$264.60	$264.60
Purchase #6	$245.86	7.160%	$263.4636	$263.46	$263.45	$263.50
Purchase #7	$94.89	5.109%	$99.7379	$99.74	$99.75	$99.70
7 purchase totals =	$1,164.23		$1,254.9830	$1,254.98	$1,254.95	$1,255.10