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	$241.32	5.555%	$254.7253	$254.73	$254.75	$254.70
Purchase #2	$92.44	4.121%	$96.2495	$96.25	$96.25	$96.20
Purchase #3	$205.44	4.115%	$213.8939	$213.89	$213.90	$213.90
Purchase #4	$174.42	13.543%	$198.0417	$198.04	$198.05	$198.00
Purchase #5	$166.71	13.186%	$188.6924	$188.69	$188.70	$188.70
Purchase #6	$136.96	13.417%	$155.3359	$155.34	$155.35	$155.30
Purchase #7	$86.60	3.559%	$89.6821	$89.68	$89.70	$89.70
7 purchase totals =	$1,103.89		$1,196.6208	$1,196.62	$1,196.70	$1,196.50