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	$174.88	4.498%	$182.7461	$182.75	$182.75	$182.70
Purchase #2	$171.54	4.631%	$179.484	$179.48	$179.50	$179.50
Purchase #3	$65.34	3.157%	$67.4028	$67.40	$67.40	$67.40
Purchase #4	$248.27	3.683%	$257.4138	$257.41	$257.40	$257.40
Purchase #5	$108.70	5.658%	$114.8502	$114.85	$114.85	$114.90
Purchase #6	$164.26	5.409%	$173.1448	$173.14	$173.15	$173.10
Purchase #7	$101.84	3.603%	$105.5093	$105.51	$105.50	$105.50
7 purchase totals =	$1,034.83		$1,080.5510	$1,080.54	$1,080.55	$1,080.50