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	$181.25	7.651%	$195.1174	$195.12	$195.10	$195.10
Purchase #2	$244.85	11.635%	$273.3383	$273.34	$273.35	$273.30
Purchase #3	$37.93	8.355%	$41.0991	$41.10	$41.10	$41.10
Purchase #4	$95.28	4.235%	$99.3151	$99.32	$99.30	$99.30
Purchase #5	$234.33	9.350%	$256.2399	$256.24	$256.25	$256.20
Purchase #6	$159.92	8.418%	$173.3821	$173.38	$173.40	$173.40
Purchase #7	$39.98	8.862%	$43.523	$43.52	$43.50	$43.50
7 purchase totals =	$993.54		$1,082.0149	$1,082.02	$1,082.00	$1,081.90