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	$182.61	7.562%	$196.419	$196.42	$196.40	$196.40
Purchase #2	$210.92	7.743%	$227.2515	$227.25	$227.25	$227.30
Purchase #3	$40.50	3.593%	$41.9552	$41.96	$41.95	$42.00
Purchase #4	$144.30	11.162%	$160.4068	$160.41	$160.40	$160.40
Purchase #5	$146.97	13.382%	$166.6375	$166.64	$166.65	$166.60
Purchase #6	$220.46	11.474%	$245.7556	$245.76	$245.75	$245.80
Purchase #7	$48.25	11.486%	$53.792	$53.79	$53.80	$53.80
7 purchase totals =	$994.01		$1,092.2176	$1,092.23	$1,092.20	$1,092.30