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	$83.72	13.443%	$94.9745	$94.97	$94.95	$95.00
Purchase #2	$32.74	13.432%	$37.1376	$37.14	$37.15	$37.10
Purchase #3	$109.59	4.337%	$114.3429	$114.34	$114.35	$114.30
Purchase #4	$123.80	7.658%	$133.2806	$133.28	$133.30	$133.30
Purchase #5	$148.67	13.353%	$168.5219	$168.52	$168.50	$168.50
Purchase #6	$107.89	8.428%	$116.983	$116.98	$117.00	$117.00
Purchase #7	$30.40	6.290%	$32.3122	$32.31	$32.30	$32.30
7 purchase totals =	$636.81		$697.5527	$697.54	$697.55	$697.50