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	$187.57	4.843%	$196.654	$196.65	$196.65	$196.70
Purchase #2	$141.41	6.438%	$150.514	$150.51	$150.50	$150.50
Purchase #3	$81.30	12.831%	$91.7316	$91.73	$91.75	$91.70
Purchase #4	$135.61	4.679%	$141.9552	$141.96	$141.95	$142.00
Purchase #5	$189.48	3.807%	$196.6935	$196.69	$196.70	$196.70
Purchase #6	$212.57	3.495%	$219.9993	$220.00	$220.00	$220.00
Purchase #7	$142.62	12.371%	$160.2635	$160.26	$160.25	$160.30
7 purchase totals =	$1,090.56		$1,157.8111	$1,157.80	$1,157.80	$1,157.90