for the local currency, EUR or in your case dollar i assume, the decimalpaces (precision) is defined in the GL Setup,
for other currencies it is defined per currency, goto the currencies list:
- a precision of more than 2 decimals is possible for amount rounding prec. and unit-amount round. prec.
- to change the precision of the invoice rounding to more than 2 decimals a custumization is needed.