Commissioner revision jurisdiction barred only by assessee's appeal to Tribunal under section 264, not by department appeal.

The Commissioner's jurisdiction to entertain a revision petition is barred under Section 264(4)(c) only when the assessee has preferred an appeal to the Appellate Tribunal; an appeal by the Department does not itself bar the Commissioner from exercising revision, because revision under Section 264 is a remedial avenue for the assessee and would be denied only by the assessee's appeal or waiver.

---

---

---