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	$160.76	7.161%	$172.272	$172.27	$172.25	$172.30
Purchase #2	$6.61	6.699%	$7.0528	$7.05	$7.05	$7.10
Purchase #3	$243.29	13.191%	$275.3824	$275.38	$275.40	$275.40
Purchase #4	$160.37	9.112%	$174.9829	$174.98	$175.00	$175.00
Purchase #5	$62.64	10.799%	$69.4045	$69.40	$69.40	$69.40
Purchase #6	$135.31	5.761%	$143.1052	$143.11	$143.10	$143.10
Purchase #7	$154.41	11.576%	$172.2845	$172.28	$172.30	$172.30
7 purchase totals =	$923.39		$1,014.4843	$1,014.47	$1,014.50	$1,014.60