Invoice Line are not allow to enter negative amount for Prepayment Invoice.

Hi everyone,
I need to enter the negative amount for one line in the prepayment invoice.
example.

Line1     200,000.00
Line2       -5,000.00

So the total amount should be 195,000.00

But I got this error:
APP-SQLAP-10678: You cannot enter a negative distribution amount on a prepayment. Please enter a positive distribution amount.

Is this the standard for Oracle?

Thanks,
Kams