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	$192.63	8.141%	$208.312	$208.31	$208.30	$208.30
Purchase #2	$61.39	9.834%	$67.4271	$67.43	$67.45	$67.40
Purchase #3	$112.25	13.155%	$127.0165	$127.02	$127.00	$127.00
Purchase #4	$179.57	3.493%	$185.8424	$185.84	$185.85	$185.80
Purchase #5	$114.36	4.340%	$119.3232	$119.32	$119.30	$119.30
Purchase #6	$130.64	8.678%	$141.9769	$141.98	$142.00	$142.00
Purchase #7	$186.27	6.759%	$198.86	$198.86	$198.85	$198.90
7 purchase totals =	$977.11		$1,048.7581	$1,048.76	$1,048.75	$1,048.70