AASHTO Brom's Method - No Overload Mentioned

[ScratchyFilm]

I was reading that Brom's method for embedment depth needs to use overload/underload factors on it. AASHTO LRFD for signs section 13 doesn't mention anything about this in their commentary about the method. Is it right to assume that the wind loads need to be adjusted to 0.6W and then rerun shear and moment with overload/underload factors on it? Without any clarification from the code, it makes it seem like you would use the loads that you would have calculated previously.