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	$201.56	4.807%	$211.249	$211.25	$211.25	$211.20
Purchase #2	$216.78	4.768%	$227.1161	$227.12	$227.10	$227.10
Purchase #3	$170.56	9.317%	$186.4511	$186.45	$186.45	$186.50
Purchase #4	$164.48	10.352%	$181.507	$181.51	$181.50	$181.50
Purchase #5	$115.38	10.371%	$127.3461	$127.35	$127.35	$127.30
Purchase #6	$188.64	8.328%	$204.3499	$204.35	$204.35	$204.30
Purchase #7	$58.95	6.786%	$62.9503	$62.95	$62.95	$63.00
7 purchase totals =	$1,116.35		$1,200.9695	$1,200.98	$1,200.95	$1,200.90