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	$33.96	4.344%	$35.4352	$35.44	$35.45	$35.40
Purchase #2	$95.79	4.144%	$99.7595	$99.76	$99.75	$99.80
Purchase #3	$88.78	4.148%	$92.4626	$92.46	$92.45	$92.50
Purchase #4	$243.91	4.614%	$255.164	$255.16	$255.15	$255.20
Purchase #5	$118.86	11.293%	$132.2829	$132.28	$132.30	$132.30
Purchase #6	$34.65	5.132%	$36.4282	$36.43	$36.45	$36.40
Purchase #7	$91.48	13.473%	$103.8051	$103.81	$103.80	$103.80
7 purchase totals =	$707.43		$755.3375	$755.34	$755.35	$755.40