That is exactly what I did. Put 0 on line 18. I already sent my return to IRS and got accepted. I am not sure though if that is what I was supposed to do even though I've been told by Turbo tax advisor. By putting 0 did not change my refund in any way. I do not know what it was there to begin with as i am not eligible to receive a deferral to start with. It is just inconvenient and annoying since it will keep popping up to review till you put a number.
