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	$233.47	9.199%	$254.9469	$254.95	$254.95	$254.90
Purchase #2	$96.54	7.873%	$104.1406	$104.14	$104.15	$104.10
Purchase #3	$179.78	4.639%	$188.12	$188.12	$188.10	$188.10
Purchase #4	$134.30	12.847%	$151.5535	$151.55	$151.55	$151.60
Purchase #5	$120.71	4.346%	$125.9561	$125.96	$125.95	$126.00
Purchase #6	$119.76	6.156%	$127.1324	$127.13	$127.15	$127.10
Purchase #7	$96.90	12.823%	$109.3255	$109.33	$109.35	$109.30
7 purchase totals =	$981.46		$1,061.1750	$1,061.18	$1,061.20	$1,061.10