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	$186.58	5.558%	$196.9501	$196.95	$196.95	$197.00
Purchase #2	$119.77	3.735%	$124.2434	$124.24	$124.25	$124.20
Purchase #3	$53.80	11.298%	$59.8783	$59.88	$59.90	$59.90
Purchase #4	$138.32	8.145%	$149.5862	$149.59	$149.60	$149.60
Purchase #5	$185.27	11.249%	$206.111	$206.11	$206.10	$206.10
Purchase #6	$185.56	11.865%	$207.5767	$207.58	$207.60	$207.60
Purchase #7	$161.76	6.415%	$172.1369	$172.14	$172.15	$172.10
7 purchase totals =	$1,031.06		$1,116.4826	$1,116.49	$1,116.55	$1,116.50