Yes.
You can add excess waiver at any time. However, if you are intending to make a claim on your policy at the time you purchase this optional upgrade, this will not remove the excesses for the claim you were already aware of.
Updated
Yes.
You can add excess waiver at any time. However, if you are intending to make a claim on your policy at the time you purchase this optional upgrade, this will not remove the excesses for the claim you were already aware of.
Updated