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	$177.33	9.378%	$193.96	$193.96	$193.95	$194.00
Purchase #2	$152.82	13.789%	$173.8923	$173.89	$173.90	$173.90
Purchase #3	$218.50	8.872%	$237.8853	$237.89	$237.90	$237.90
Purchase #4	$52.51	13.852%	$59.7837	$59.78	$59.80	$59.80
Purchase #5	$58.97	11.136%	$65.5369	$65.54	$65.55	$65.50
Purchase #6	$219.73	8.458%	$238.3148	$238.31	$238.30	$238.30
Purchase #7	$37.86	10.248%	$41.7399	$41.74	$41.75	$41.70
7 purchase totals =	$917.72		$1,011.1129	$1,011.11	$1,011.15	$1,011.10