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	$198.86	7.587%	$213.9475	$213.95	$213.95	$213.90
Purchase #2	$206.93	11.842%	$231.4347	$231.43	$231.45	$231.40
Purchase #3	$36.73	3.772%	$38.1155	$38.12	$38.10	$38.10
Purchase #4	$155.37	5.775%	$164.3426	$164.34	$164.35	$164.30
Purchase #5	$186.92	7.512%	$200.9614	$200.96	$200.95	$201.00
Purchase #6	$35.72	12.358%	$40.1343	$40.13	$40.15	$40.10
Purchase #7	$144.27	5.800%	$152.6377	$152.64	$152.65	$152.60
7 purchase totals =	$964.80		$1,041.5737	$1,041.57	$1,041.60	$1,041.40