If conditions are revealed during construction which will require minor modification of already approved plans and specifications, the moratorium permit may be amended upon written application to the central tidal wetland permit administrator who may for good cause shown permit such amendment if such modification will not be contrary to the policy or provisions of the act; provided, however, that in cases of doubt as to the substantiality of such modification or whether or not it will be contrary to the policy or provisions of the act, the central tidal wetlands permit administrator shall treat such application as a petition for a moratorium permit and require the holder of a moratorium permit to file a new petition under section 660.3 of this Part.