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	$56.39	7.625%	$60.6897	$60.69	$60.70	$60.70
Purchase #2	$181.40	10.279%	$200.0461	$200.05	$200.05	$200.00
Purchase #3	$68.92	6.765%	$73.5824	$73.58	$73.60	$73.60
Purchase #4	$173.88	6.436%	$185.0709	$185.07	$185.05	$185.10
Purchase #5	$215.67	4.624%	$225.6426	$225.64	$225.65	$225.60
Purchase #6	$88.33	13.322%	$100.0973	$100.10	$100.10	$100.10
Purchase #7	$102.90	6.229%	$109.3096	$109.31	$109.30	$109.30
7 purchase totals =	$887.49		$954.4386	$954.44	$954.45	$954.40