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	$174.98	12.221%	$196.3643	$196.36	$196.35	$196.40
Purchase #2	$98.70	6.637%	$105.2507	$105.25	$105.25	$105.30
Purchase #3	$157.31	10.588%	$173.966	$173.97	$173.95	$174.00
Purchase #4	$98.91	6.517%	$105.356	$105.36	$105.35	$105.40
Purchase #5	$182.69	7.483%	$196.3607	$196.36	$196.35	$196.40
Purchase #6	$126.54	11.493%	$141.0832	$141.08	$141.10	$141.10
Purchase #7	$127.93	10.496%	$141.3575	$141.36	$141.35	$141.40
7 purchase totals =	$967.06		$1,059.7384	$1,059.74	$1,059.70	$1,060.00