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	$158.33	5.821%	$167.5464	$167.55	$167.55	$167.50
Purchase #2	$68.71	4.427%	$71.7518	$71.75	$71.75	$71.80
Purchase #3	$135.60	6.347%	$144.2065	$144.21	$144.20	$144.20
Purchase #4	$169.86	10.119%	$187.0481	$187.05	$187.05	$187.00
Purchase #5	$125.50	6.223%	$133.3099	$133.31	$133.30	$133.30
Purchase #6	$73.94	11.214%	$82.2316	$82.23	$82.25	$82.20
Purchase #7	$230.43	4.319%	$240.3823	$240.38	$240.40	$240.40
7 purchase totals =	$962.37		$1,026.4766	$1,026.48	$1,026.50	$1,026.40