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	$35.68	3.565%	$36.952	$36.95	$36.95	$37.00
Purchase #2	$86.91	10.597%	$96.1199	$96.12	$96.10	$96.10
Purchase #3	$63.84	11.613%	$71.2537	$71.25	$71.25	$71.30
Purchase #4	$203.72	10.501%	$225.1126	$225.11	$225.10	$225.10
Purchase #5	$221.27	3.443%	$228.8883	$228.89	$228.90	$228.90
Purchase #6	$250.72	3.271%	$258.9211	$258.92	$258.90	$258.90
Purchase #7	$87.37	10.805%	$96.8103	$96.81	$96.80	$96.80
7 purchase totals =	$949.51		$1,014.0579	$1,014.05	$1,014.00	$1,014.10