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	$211.75	3.687%	$219.5572	$219.56	$219.55	$219.60
Purchase #2	$228.53	13.498%	$259.377	$259.38	$259.40	$259.40
Purchase #3	$40.93	5.841%	$43.3207	$43.32	$43.30	$43.30
Purchase #4	$197.69	13.159%	$223.704	$223.70	$223.70	$223.70
Purchase #5	$79.70	4.717%	$83.4594	$83.46	$83.45	$83.50
Purchase #6	$26.56	4.742%	$27.8195	$27.82	$27.80	$27.80
Purchase #7	$226.99	5.154%	$238.6891	$238.69	$238.70	$238.70
7 purchase totals =	$1,012.15		$1,095.9269	$1,095.93	$1,095.90	$1,096.00