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	$186.94	5.348%	$196.9376	$196.94	$196.95	$196.90
Purchase #2	$118.51	9.692%	$129.996	$130.00	$130.00	$130.00
Purchase #3	$162.73	11.391%	$181.2666	$181.27	$181.25	$181.30
Purchase #4	$159.31	9.764%	$174.865	$174.87	$174.85	$174.90
Purchase #5	$38.27	6.282%	$40.6741	$40.67	$40.65	$40.70
Purchase #6	$78.57	4.244%	$81.9045	$81.90	$81.90	$81.90
Purchase #7	$216.36	11.765%	$241.8148	$241.81	$241.80	$241.80
7 purchase totals =	$960.69		$1,047.4586	$1,047.46	$1,047.40	$1,047.50