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	$219.40	3.707%	$227.5332	$227.53	$227.55	$227.50
Purchase #2	$38.53	4.685%	$40.3351	$40.34	$40.35	$40.30
Purchase #3	$85.63	7.385%	$91.9538	$91.95	$91.95	$92.00
Purchase #4	$218.43	11.350%	$243.2218	$243.22	$243.20	$243.20
Purchase #5	$89.63	11.155%	$99.6282	$99.63	$99.65	$99.60
Purchase #6	$199.82	8.375%	$216.5549	$216.55	$216.55	$216.60
Purchase #7	$196.42	4.747%	$205.7441	$205.74	$205.75	$205.70
7 purchase totals =	$1,047.86		$1,124.9711	$1,124.96	$1,125.00	$1,124.90