When statements of witnesses are made basis of demand, not allowing assessee to cross-examine witnesses is a serious flaw which makes order nullity, as it amounts to violation of principles of natural justice - It is not for adjudicating authority or Tribunal to have guesswork as to for what purposes assessee wanted to cross-examine witnesses and what extraction assessee wanted from them- Andaman Timber Industries [2015] 62 taxmann.com 3 (SC) SUPREME COURT OF INDIA SEPTEMBER 2, 2015