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	$164.86	4.528%	$172.3249	$172.32	$172.30	$172.30
Purchase #2	$145.52	4.585%	$152.1921	$152.19	$152.20	$152.20
Purchase #3	$100.64	4.559%	$105.2282	$105.23	$105.25	$105.20
Purchase #4	$179.54	8.494%	$194.7901	$194.79	$194.80	$194.80
Purchase #5	$47.44	4.605%	$49.6246	$49.62	$49.60	$49.60
Purchase #6	$200.30	10.153%	$220.6365	$220.64	$220.65	$220.60
Purchase #7	$119.70	9.787%	$131.415	$131.42	$131.40	$131.40
7 purchase totals =	$958.00		$1,026.2114	$1,026.21	$1,026.20	$1,026.10