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	$106.54	4.131%	$110.9412	$110.94	$110.95	$110.90
Purchase #2	$115.93	10.151%	$127.6981	$127.70	$127.70	$127.70
Purchase #3	$168.60	9.745%	$185.0301	$185.03	$185.05	$185.00
Purchase #4	$45.65	3.253%	$47.135	$47.14	$47.15	$47.10
Purchase #5	$78.54	4.441%	$82.028	$82.03	$82.05	$82.00
Purchase #6	$247.34	11.504%	$275.794	$275.79	$275.80	$275.80
Purchase #7	$225.78	13.148%	$255.4656	$255.47	$255.45	$255.50
7 purchase totals =	$988.38		$1,084.0920	$1,084.10	$1,084.15	$1,084.00