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	$230.56	4.760%	$241.5347	$241.53	$241.55	$241.50
Purchase #2	$27.50	7.209%	$29.4825	$29.48	$29.50	$29.50
Purchase #3	$105.92	6.669%	$112.9838	$112.98	$113.00	$113.00
Purchase #4	$182.56	6.339%	$194.1325	$194.13	$194.15	$194.10
Purchase #5	$52.39	7.427%	$56.281	$56.28	$56.30	$56.30
Purchase #6	$127.45	11.682%	$142.3387	$142.34	$142.35	$142.30
Purchase #7	$114.78	3.502%	$118.7996	$118.80	$118.80	$118.80
7 purchase totals =	$841.16		$895.5528	$895.54	$895.65	$895.50