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	$98.61	9.462%	$107.9405	$107.94	$107.95	$107.90
Purchase #2	$7.42	6.698%	$7.917	$7.92	$7.90	$7.90
Purchase #3	$193.35	10.815%	$214.2608	$214.26	$214.25	$214.30
Purchase #4	$244.47	3.643%	$253.376	$253.38	$253.40	$253.40
Purchase #5	$141.64	12.486%	$159.3252	$159.33	$159.35	$159.30
Purchase #6	$105.71	3.336%	$109.2365	$109.24	$109.25	$109.20
Purchase #7	$193.58	8.165%	$209.3858	$209.39	$209.40	$209.40
7 purchase totals =	$984.78		$1,061.4418	$1,061.46	$1,061.50	$1,061.40