How do increase invoice QTY column to accept decimals?

Cannot figure out how to enter a number with 2 decimal points in the QTY column on the invoice form. Such as: 1234.56; apparently it will only accept 1234.5. This is unacceptable and unprofessional when trying to invoice a customer. Is there a workaround? Don't suggest I put the second half of the quantity on the second line. Tech support has already told me to do that. NEED A FIX, PLEASE!!!