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	$236.29	3.709%	$245.054	$245.05	$245.05	$245.10
Purchase #2	$229.56	3.693%	$238.0377	$238.04	$238.05	$238.00
Purchase #3	$234.80	13.411%	$266.289	$266.29	$266.30	$266.30
Purchase #4	$200.44	4.498%	$209.4558	$209.46	$209.45	$209.50
Purchase #5	$177.69	6.667%	$189.5366	$189.54	$189.55	$189.50
Purchase #6	$89.47	3.495%	$92.597	$92.60	$92.60	$92.60
Purchase #7	$234.57	7.214%	$251.4919	$251.49	$251.50	$251.50
7 purchase totals =	$1,402.82		$1,492.4620	$1,492.47	$1,492.50	$1,492.50