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	$95.82	5.431%	$101.024	$101.02	$101.00	$101.00
Purchase #2	$71.28	10.317%	$78.634	$78.63	$78.65	$78.60
Purchase #3	$118.98	11.116%	$132.2058	$132.21	$132.20	$132.20
Purchase #4	$214.56	6.426%	$228.3476	$228.35	$228.35	$228.30
Purchase #5	$83.56	7.498%	$89.8253	$89.83	$89.85	$89.80
Purchase #6	$33.46	12.328%	$37.5849	$37.58	$37.60	$37.60
Purchase #7	$244.71	8.212%	$264.8056	$264.81	$264.80	$264.80
7 purchase totals =	$862.37		$932.4272	$932.43	$932.45	$932.30