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	$201.55	10.259%	$222.227	$222.23	$222.25	$222.20
Purchase #2	$41.55	5.168%	$43.6973	$43.70	$43.70	$43.70
Purchase #3	$62.85	3.292%	$64.919	$64.92	$64.90	$64.90
Purchase #4	$53.70	10.450%	$59.3117	$59.31	$59.30	$59.30
Purchase #5	$138.62	6.713%	$147.9256	$147.93	$147.95	$147.90
Purchase #6	$226.69	7.659%	$244.0522	$244.05	$244.05	$244.10
Purchase #7	$217.27	12.232%	$243.8465	$243.85	$243.85	$243.80
7 purchase totals =	$942.23		$1,025.9793	$1,025.99	$1,026.00	$1,025.90