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	$177.66	10.772%	$196.7975	$196.80	$196.80	$196.80
Purchase #2	$66.68	4.118%	$69.4259	$69.43	$69.45	$69.40
Purchase #3	$56.49	5.200%	$59.4275	$59.43	$59.45	$59.40
Purchase #4	$88.96	13.478%	$100.95	$100.95	$100.95	$101.00
Purchase #5	$239.57	4.734%	$250.9112	$250.91	$250.90	$250.90
Purchase #6	$109.75	7.815%	$118.327	$118.33	$118.35	$118.30
Purchase #7	$212.64	11.123%	$236.2919	$236.29	$236.30	$236.30
7 purchase totals =	$951.75		$1,032.1310	$1,032.14	$1,032.20	$1,032.10