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	$139.83	9.156%	$152.6328	$152.63	$152.65	$152.60
Purchase #2	$41.94	3.642%	$43.4675	$43.47	$43.45	$43.50
Purchase #3	$62.83	4.136%	$65.4286	$65.43	$65.45	$65.40
Purchase #4	$229.41	8.242%	$248.318	$248.32	$248.30	$248.30
Purchase #5	$205.45	4.393%	$214.4754	$214.48	$214.50	$214.50
Purchase #6	$167.61	9.787%	$184.014	$184.01	$184.00	$184.00
Purchase #7	$85.91	8.739%	$93.4177	$93.42	$93.40	$93.40
7 purchase totals =	$932.98		$1,001.7540	$1,001.76	$1,001.75	$1,001.70