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	$196.30	11.631%	$219.1317	$219.13	$219.15	$219.10
Purchase #2	$227.91	6.207%	$242.0564	$242.06	$242.05	$242.10
Purchase #3	$74.49	3.128%	$76.82	$76.82	$76.80	$76.80
Purchase #4	$82.85	3.443%	$85.7025	$85.70	$85.70	$85.70
Purchase #5	$126.89	9.362%	$138.7694	$138.77	$138.75	$138.80
Purchase #6	$240.46	10.476%	$265.6506	$265.65	$265.65	$265.70
Purchase #7	$119.30	6.798%	$127.41	$127.41	$127.40	$127.40
7 purchase totals =	$1,068.20		$1,155.5406	$1,155.54	$1,155.50	$1,155.60