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	$188.29	4.392%	$196.5597	$196.56	$196.55	$196.60
Purchase #2	$93.63	6.386%	$99.6092	$99.61	$99.60	$99.60
Purchase #3	$27.32	13.417%	$30.9855	$30.99	$31.00	$31.00
Purchase #4	$188.43	4.492%	$196.8943	$196.89	$196.90	$196.90
Purchase #5	$248.29	11.698%	$277.335	$277.34	$277.35	$277.30
Purchase #6	$22.26	7.848%	$24.007	$24.01	$24.00	$24.00
Purchase #7	$187.31	12.441%	$210.6132	$210.61	$210.60	$210.60
7 purchase totals =	$955.53		$1,036.0039	$1,036.01	$1,036.00	$1,036.00