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	$174.78	6.389%	$185.9467	$185.95	$185.95	$185.90
Purchase #2	$7.34	5.229%	$7.7238	$7.72	$7.70	$7.70
Purchase #3	$38.32	10.843%	$42.475	$42.48	$42.50	$42.50
Purchase #4	$194.41	5.609%	$205.3145	$205.31	$205.30	$205.30
Purchase #5	$238.28	4.215%	$248.3235	$248.32	$248.30	$248.30
Purchase #6	$227.79	3.388%	$235.5075	$235.51	$235.50	$235.50
Purchase #7	$91.38	7.165%	$97.9274	$97.93	$97.95	$97.90
7 purchase totals =	$972.30		$1,023.2184	$1,023.22	$1,023.20	$1,023.10