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	$120.53	3.695%	$124.9836	$124.98	$125.00	$125.00
Purchase #2	$72.73	7.268%	$78.016	$78.02	$78.00	$78.00
Purchase #3	$175.25	3.850%	$181.9971	$182.00	$182.00	$182.00
Purchase #4	$54.85	8.816%	$59.6856	$59.69	$59.70	$59.70
Purchase #5	$171.25	6.672%	$182.6758	$182.68	$182.70	$182.70
Purchase #6	$247.69	6.320%	$263.344	$263.34	$263.35	$263.30
Purchase #7	$238.58	7.410%	$256.2588	$256.26	$256.25	$256.30
7 purchase totals =	$1,080.88		$1,146.9609	$1,146.97	$1,147.00	$1,147.00