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	$196.34	3.813%	$203.8264	$203.83	$203.85	$203.80
Purchase #2	$11.46	3.677%	$11.8814	$11.88	$11.90	$11.90
Purchase #3	$68.42	4.420%	$71.4442	$71.44	$71.45	$71.40
Purchase #4	$238.39	10.518%	$263.4639	$263.46	$263.45	$263.50
Purchase #5	$43.38	4.674%	$45.4076	$45.41	$45.40	$45.40
Purchase #6	$157.66	8.778%	$171.4994	$171.50	$171.50	$171.50
Purchase #7	$173.31	4.264%	$180.6999	$180.70	$180.70	$180.70
7 purchase totals =	$888.96		$948.2228	$948.22	$948.25	$948.20