This article is an addendum to [ 1]. We extend our computation of the onshell scattering amplitudes in an arbitrary inflaton background (phi) over bar (1). Although the effective Einstein frame cutoff for (phi) over bar (1) >> MP /root xi turns out to be <<(phi)over bar> or xi(phi) over bar (1) for the U(1) model, this is not the case for the realistic doublet Higgs model where the effective Einstein frame cutoff turns out to be the standard MP /root xi for both the Palatini and metric formulations. However, as it has been pointed out in [1] the background (phi) over bar (1) is the effective Jordan frame cutoff in all cases for both the Palatini and metric formalisms.