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	$237.98	10.745%	$263.551	$263.55	$263.55	$263.60
Purchase #2	$73.67	4.323%	$76.8548	$76.85	$76.85	$76.90
Purchase #3	$64.39	12.236%	$72.2688	$72.27	$72.25	$72.30
Purchase #4	$199.78	10.534%	$220.8248	$220.82	$220.80	$220.80
Purchase #5	$55.36	3.447%	$57.2683	$57.27	$57.25	$57.30
Purchase #6	$223.47	9.535%	$244.7779	$244.78	$244.80	$244.80
Purchase #7	$143.94	10.796%	$159.4798	$159.48	$159.50	$159.50
7 purchase totals =	$998.59		$1,095.0254	$1,095.02	$1,095.00	$1,095.20