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	$195.41	7.590%	$210.2416	$210.24	$210.25	$210.20
Purchase #2	$189.72	13.848%	$215.9924	$215.99	$216.00	$216.00
Purchase #3	$153.45	4.130%	$159.7875	$159.79	$159.80	$159.80
Purchase #4	$162.87	3.479%	$168.5362	$168.54	$168.55	$168.50
Purchase #5	$180.87	8.543%	$196.3217	$196.32	$196.30	$196.30
Purchase #6	$207.66	11.226%	$230.9719	$230.97	$230.95	$231.00
Purchase #7	$211.90	3.766%	$219.8802	$219.88	$219.90	$219.90
7 purchase totals =	$1,301.88		$1,401.7315	$1,401.73	$1,401.75	$1,401.70