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	$44.92	4.508%	$46.945	$46.95	$46.95	$46.90
Purchase #2	$12.75	3.675%	$13.2186	$13.22	$13.20	$13.20
Purchase #3	$195.89	10.804%	$217.054	$217.05	$217.05	$217.10
Purchase #4	$243.27	4.740%	$254.801	$254.80	$254.80	$254.80
Purchase #5	$115.92	13.575%	$131.6561	$131.66	$131.65	$131.70
Purchase #6	$121.26	12.592%	$136.5291	$136.53	$136.55	$136.50
Purchase #7	$238.28	9.764%	$261.5457	$261.55	$261.55	$261.50
7 purchase totals =	$972.29		$1,061.7495	$1,061.76	$1,061.75	$1,061.70