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	$213.74	6.365%	$227.3446	$227.34	$227.35	$227.30
Purchase #2	$214.94	5.757%	$227.3141	$227.31	$227.30	$227.30
Purchase #3	$85.92	12.380%	$96.5569	$96.56	$96.55	$96.60
Purchase #4	$53.72	9.175%	$58.6488	$58.65	$58.65	$58.60
Purchase #5	$147.64	12.500%	$166.095	$166.10	$166.10	$166.10
Purchase #6	$157.27	3.151%	$162.2256	$162.23	$162.25	$162.20
Purchase #7	$76.50	11.601%	$85.3748	$85.37	$85.35	$85.40
7 purchase totals =	$949.73		$1,023.5598	$1,023.56	$1,023.55	$1,023.50