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	$213.98	5.454%	$225.6505	$225.65	$225.65	$225.70
Purchase #2	$67.30	5.288%	$70.8588	$70.86	$70.85	$70.90
Purchase #3	$192.32	6.330%	$204.4939	$204.49	$204.50	$204.50
Purchase #4	$212.77	7.399%	$228.5129	$228.51	$228.50	$228.50
Purchase #5	$172.35	9.454%	$188.644	$188.64	$188.65	$188.60
Purchase #6	$169.40	5.578%	$178.8491	$178.85	$178.85	$178.80
Purchase #7	$66.62	7.256%	$71.4539	$71.45	$71.45	$71.50
7 purchase totals =	$1,094.74		$1,168.4631	$1,168.45	$1,168.45	$1,168.50