Old Age Security with negative "GIS" amount - how to enter?

I have a client with an old age security slip that has a “negative” GIS amount. GIS was overpaid the prior year so she had to repay it. Computer will not allow me to enter the negative amount.

Although GIS is not taxable, the negative amount would reduce the total and net income and impact income-tested fees, such as personal care home costs.

Funny, the AFR does not seem to import the negative amount either.

How about putting it in the Other Deductions line as a write in.

AFR is handling the situation correctly. If a client had to repay more supplement than they received in a year it does not get reported on the T1 return.