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	$110.45	3.187%	$113.97	$113.97	$113.95	$114.00
Purchase #2	$67.27	6.437%	$71.6002	$71.60	$71.60	$71.60
Purchase #3	$152.29	9.671%	$167.018	$167.02	$167.00	$167.00
Purchase #4	$221.54	11.526%	$247.0747	$247.07	$247.05	$247.10
Purchase #5	$219.47	11.411%	$244.5137	$244.51	$244.50	$244.50
Purchase #6	$145.92	3.668%	$151.2723	$151.27	$151.25	$151.30
Purchase #7	$25.47	7.198%	$27.3033	$27.30	$27.30	$27.30
7 purchase totals =	$942.41		$1,022.7522	$1,022.74	$1,022.65	$1,022.80